freebsd-dev/sys/kern/kern_dump.c

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/*-
* Copyright (c) 2002 Marcel Moolenaar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/cons.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/kerneldump.h>
#include <sys/watchdog.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <machine/dump.h>
#include <machine/elf.h>
#include <machine/md_var.h>
#include <machine/pcb.h>
CTASSERT(sizeof(struct kerneldumpheader) == 512);
#define MD_ALIGN(x) roundup2((off_t)(x), PAGE_SIZE)
/* Handle buffered writes. */
static size_t fragsz;
struct dump_pa dump_map[DUMPSYS_MD_PA_NPAIRS];
#if !defined(__powerpc__) && !defined(__sparc__)
void
dumpsys_gen_pa_init(void)
{
int n, idx;
bzero(dump_map, sizeof(dump_map));
for (n = 0; n < nitems(dump_map); n++) {
idx = n * 2;
if (dump_avail[idx] == 0 && dump_avail[idx + 1] == 0)
break;
dump_map[n].pa_start = dump_avail[idx];
dump_map[n].pa_size = dump_avail[idx + 1] - dump_avail[idx];
}
}
#endif
struct dump_pa *
dumpsys_gen_pa_next(struct dump_pa *mdp)
{
if (mdp == NULL)
return (&dump_map[0]);
mdp++;
if (mdp->pa_size == 0)
mdp = NULL;
return (mdp);
}
void
dumpsys_gen_wbinv_all(void)
{
}
void
dumpsys_gen_unmap_chunk(vm_paddr_t pa __unused, size_t chunk __unused,
void *va __unused)
{
}
#if !defined(__sparc__)
int
dumpsys_gen_write_aux_headers(struct dumperinfo *di)
{
return (0);
}
#endif
Add support for encrypted kernel crash dumps. Changes include modifications in kernel crash dump routines, dumpon(8) and savecore(8). A new tool called decryptcore(8) was added. A new DIOCSKERNELDUMP I/O control was added to send a kernel crash dump configuration in the diocskerneldump_arg structure to the kernel. The old DIOCSKERNELDUMP I/O control was renamed to DIOCSKERNELDUMP_FREEBSD11 for backward ABI compatibility. dumpon(8) generates an one-time random symmetric key and encrypts it using an RSA public key in capability mode. Currently only AES-256-CBC is supported but EKCD was designed to implement support for other algorithms in the future. The public key is chosen using the -k flag. The dumpon rc(8) script can do this automatically during startup using the dumppubkey rc.conf(5) variable. Once the keys are calculated dumpon sends them to the kernel via DIOCSKERNELDUMP I/O control. When the kernel receives the DIOCSKERNELDUMP I/O control it generates a random IV and sets up the key schedule for the specified algorithm. Each time the kernel tries to write a crash dump to the dump device, the IV is replaced by a SHA-256 hash of the previous value. This is intended to make a possible differential cryptanalysis harder since it is possible to write multiple crash dumps without reboot by repeating the following commands: # sysctl debug.kdb.enter=1 db> call doadump(0) db> continue # savecore A kernel dump key consists of an algorithm identifier, an IV and an encrypted symmetric key. The kernel dump key size is included in a kernel dump header. The size is an unsigned 32-bit integer and it is aligned to a block size. The header structure has 512 bytes to match the block size so it was required to make a panic string 4 bytes shorter to add a new field to the header structure. If the kernel dump key size in the header is nonzero it is assumed that the kernel dump key is placed after the first header on the dump device and the core dump is encrypted. Separate functions were implemented to write the kernel dump header and the kernel dump key as they need to be unencrypted. The dump_write function encrypts data if the kernel was compiled with the EKCD option. Encrypted kernel textdumps are not supported due to the way they are constructed which makes it impossible to use the CBC mode for encryption. It should be also noted that textdumps don't contain sensitive data by design as a user decides what information should be dumped. savecore(8) writes the kernel dump key to a key.# file if its size in the header is nonzero. # is the number of the current core dump. decryptcore(8) decrypts the core dump using a private RSA key and the kernel dump key. This is performed by a child process in capability mode. If the decryption was not successful the parent process removes a partially decrypted core dump. Description on how to encrypt crash dumps was added to the decryptcore(8), dumpon(8), rc.conf(5) and savecore(8) manual pages. EKCD was tested on amd64 using bhyve and i386, mipsel and sparc64 using QEMU. The feature still has to be tested on arm and arm64 as it wasn't possible to run FreeBSD due to the problems with QEMU emulation and lack of hardware. Designed by: def, pjd Reviewed by: cem, oshogbo, pjd Partial review: delphij, emaste, jhb, kib Approved by: pjd (mentor) Differential Revision: https://reviews.freebsd.org/D4712
2016-12-10 16:20:39 +00:00
int
dumpsys_buf_seek(struct dumperinfo *di, size_t sz)
{
static uint8_t buf[DEV_BSIZE];
size_t nbytes;
int error;
bzero(buf, sizeof(buf));
while (sz > 0) {
nbytes = MIN(sz, sizeof(buf));
error = dump_append(di, buf, 0, nbytes);
Add support for encrypted kernel crash dumps. Changes include modifications in kernel crash dump routines, dumpon(8) and savecore(8). A new tool called decryptcore(8) was added. A new DIOCSKERNELDUMP I/O control was added to send a kernel crash dump configuration in the diocskerneldump_arg structure to the kernel. The old DIOCSKERNELDUMP I/O control was renamed to DIOCSKERNELDUMP_FREEBSD11 for backward ABI compatibility. dumpon(8) generates an one-time random symmetric key and encrypts it using an RSA public key in capability mode. Currently only AES-256-CBC is supported but EKCD was designed to implement support for other algorithms in the future. The public key is chosen using the -k flag. The dumpon rc(8) script can do this automatically during startup using the dumppubkey rc.conf(5) variable. Once the keys are calculated dumpon sends them to the kernel via DIOCSKERNELDUMP I/O control. When the kernel receives the DIOCSKERNELDUMP I/O control it generates a random IV and sets up the key schedule for the specified algorithm. Each time the kernel tries to write a crash dump to the dump device, the IV is replaced by a SHA-256 hash of the previous value. This is intended to make a possible differential cryptanalysis harder since it is possible to write multiple crash dumps without reboot by repeating the following commands: # sysctl debug.kdb.enter=1 db> call doadump(0) db> continue # savecore A kernel dump key consists of an algorithm identifier, an IV and an encrypted symmetric key. The kernel dump key size is included in a kernel dump header. The size is an unsigned 32-bit integer and it is aligned to a block size. The header structure has 512 bytes to match the block size so it was required to make a panic string 4 bytes shorter to add a new field to the header structure. If the kernel dump key size in the header is nonzero it is assumed that the kernel dump key is placed after the first header on the dump device and the core dump is encrypted. Separate functions were implemented to write the kernel dump header and the kernel dump key as they need to be unencrypted. The dump_write function encrypts data if the kernel was compiled with the EKCD option. Encrypted kernel textdumps are not supported due to the way they are constructed which makes it impossible to use the CBC mode for encryption. It should be also noted that textdumps don't contain sensitive data by design as a user decides what information should be dumped. savecore(8) writes the kernel dump key to a key.# file if its size in the header is nonzero. # is the number of the current core dump. decryptcore(8) decrypts the core dump using a private RSA key and the kernel dump key. This is performed by a child process in capability mode. If the decryption was not successful the parent process removes a partially decrypted core dump. Description on how to encrypt crash dumps was added to the decryptcore(8), dumpon(8), rc.conf(5) and savecore(8) manual pages. EKCD was tested on amd64 using bhyve and i386, mipsel and sparc64 using QEMU. The feature still has to be tested on arm and arm64 as it wasn't possible to run FreeBSD due to the problems with QEMU emulation and lack of hardware. Designed by: def, pjd Reviewed by: cem, oshogbo, pjd Partial review: delphij, emaste, jhb, kib Approved by: pjd (mentor) Differential Revision: https://reviews.freebsd.org/D4712
2016-12-10 16:20:39 +00:00
if (error)
return (error);
sz -= nbytes;
}
return (0);
}
int
dumpsys_buf_write(struct dumperinfo *di, char *ptr, size_t sz)
{
size_t len;
int error;
while (sz) {
len = di->blocksize - fragsz;
if (len > sz)
len = sz;
memcpy((char *)di->blockbuf + fragsz, ptr, len);
fragsz += len;
ptr += len;
sz -= len;
if (fragsz == di->blocksize) {
error = dump_append(di, di->blockbuf, 0, di->blocksize);
if (error)
return (error);
fragsz = 0;
}
}
return (0);
}
int
dumpsys_buf_flush(struct dumperinfo *di)
{
int error;
if (fragsz == 0)
return (0);
error = dump_append(di, di->blockbuf, 0, di->blocksize);
fragsz = 0;
return (error);
}
CTASSERT(PAGE_SHIFT < 20);
#define PG2MB(pgs) ((pgs + (1 << (20 - PAGE_SHIFT)) - 1) >> (20 - PAGE_SHIFT))
int
dumpsys_cb_dumpdata(struct dump_pa *mdp, int seqnr, void *arg)
{
struct dumperinfo *di = (struct dumperinfo*)arg;
vm_paddr_t pa;
void *va;
uint64_t pgs;
size_t counter, sz, chunk;
int c, error;
u_int maxdumppgs;
error = 0; /* catch case in which chunk size is 0 */
counter = 0; /* Update twiddle every 16MB */
va = NULL;
pgs = mdp->pa_size / PAGE_SIZE;
pa = mdp->pa_start;
maxdumppgs = min(di->maxiosize / PAGE_SIZE, MAXDUMPPGS);
if (maxdumppgs == 0) /* seatbelt */
maxdumppgs = 1;
printf(" chunk %d: %juMB (%ju pages)", seqnr, (uintmax_t)PG2MB(pgs),
(uintmax_t)pgs);
dumpsys_wbinv_all();
while (pgs) {
chunk = pgs;
if (chunk > maxdumppgs)
chunk = maxdumppgs;
sz = chunk << PAGE_SHIFT;
counter += sz;
if (counter >> 24) {
printf(" %ju", (uintmax_t)PG2MB(pgs));
counter &= (1 << 24) - 1;
}
dumpsys_map_chunk(pa, chunk, &va);
wdog_kern_pat(WD_LASTVAL);
error = dump_append(di, va, 0, sz);
dumpsys_unmap_chunk(pa, chunk, va);
if (error)
break;
pgs -= chunk;
pa += sz;
/* Check for user abort. */
c = cncheckc();
if (c == 0x03)
return (ECANCELED);
if (c != -1)
printf(" (CTRL-C to abort) ");
}
printf(" ... %s\n", (error) ? "fail" : "ok");
return (error);
}
int
dumpsys_foreach_chunk(dumpsys_callback_t cb, void *arg)
{
struct dump_pa *mdp;
int error, seqnr;
seqnr = 0;
mdp = dumpsys_pa_next(NULL);
while (mdp != NULL) {
error = (*cb)(mdp, seqnr++, arg);
if (error)
return (-error);
mdp = dumpsys_pa_next(mdp);
}
return (seqnr);
}
#if !defined(__sparc__)
static off_t fileofs;
static int
cb_dumphdr(struct dump_pa *mdp, int seqnr, void *arg)
{
struct dumperinfo *di = (struct dumperinfo*)arg;
Elf_Phdr phdr;
uint64_t size;
int error;
size = mdp->pa_size;
bzero(&phdr, sizeof(phdr));
phdr.p_type = PT_LOAD;
phdr.p_flags = PF_R; /* XXX */
phdr.p_offset = fileofs;
#ifdef __powerpc__
phdr.p_vaddr = (do_minidump? mdp->pa_start : ~0L);
phdr.p_paddr = (do_minidump? ~0L : mdp->pa_start);
#else
phdr.p_vaddr = mdp->pa_start;
phdr.p_paddr = mdp->pa_start;
#endif
phdr.p_filesz = size;
phdr.p_memsz = size;
phdr.p_align = PAGE_SIZE;
error = dumpsys_buf_write(di, (char*)&phdr, sizeof(phdr));
fileofs += phdr.p_filesz;
return (error);
}
static int
cb_size(struct dump_pa *mdp, int seqnr, void *arg)
{
uint64_t *sz;
sz = (uint64_t *)arg;
*sz += (uint64_t)mdp->pa_size;
return (0);
}
int
dumpsys_generic(struct dumperinfo *di)
{
static struct kerneldumpheader kdh;
Elf_Ehdr ehdr;
uint64_t dumpsize;
off_t hdrgap;
Add support for encrypted kernel crash dumps. Changes include modifications in kernel crash dump routines, dumpon(8) and savecore(8). A new tool called decryptcore(8) was added. A new DIOCSKERNELDUMP I/O control was added to send a kernel crash dump configuration in the diocskerneldump_arg structure to the kernel. The old DIOCSKERNELDUMP I/O control was renamed to DIOCSKERNELDUMP_FREEBSD11 for backward ABI compatibility. dumpon(8) generates an one-time random symmetric key and encrypts it using an RSA public key in capability mode. Currently only AES-256-CBC is supported but EKCD was designed to implement support for other algorithms in the future. The public key is chosen using the -k flag. The dumpon rc(8) script can do this automatically during startup using the dumppubkey rc.conf(5) variable. Once the keys are calculated dumpon sends them to the kernel via DIOCSKERNELDUMP I/O control. When the kernel receives the DIOCSKERNELDUMP I/O control it generates a random IV and sets up the key schedule for the specified algorithm. Each time the kernel tries to write a crash dump to the dump device, the IV is replaced by a SHA-256 hash of the previous value. This is intended to make a possible differential cryptanalysis harder since it is possible to write multiple crash dumps without reboot by repeating the following commands: # sysctl debug.kdb.enter=1 db> call doadump(0) db> continue # savecore A kernel dump key consists of an algorithm identifier, an IV and an encrypted symmetric key. The kernel dump key size is included in a kernel dump header. The size is an unsigned 32-bit integer and it is aligned to a block size. The header structure has 512 bytes to match the block size so it was required to make a panic string 4 bytes shorter to add a new field to the header structure. If the kernel dump key size in the header is nonzero it is assumed that the kernel dump key is placed after the first header on the dump device and the core dump is encrypted. Separate functions were implemented to write the kernel dump header and the kernel dump key as they need to be unencrypted. The dump_write function encrypts data if the kernel was compiled with the EKCD option. Encrypted kernel textdumps are not supported due to the way they are constructed which makes it impossible to use the CBC mode for encryption. It should be also noted that textdumps don't contain sensitive data by design as a user decides what information should be dumped. savecore(8) writes the kernel dump key to a key.# file if its size in the header is nonzero. # is the number of the current core dump. decryptcore(8) decrypts the core dump using a private RSA key and the kernel dump key. This is performed by a child process in capability mode. If the decryption was not successful the parent process removes a partially decrypted core dump. Description on how to encrypt crash dumps was added to the decryptcore(8), dumpon(8), rc.conf(5) and savecore(8) manual pages. EKCD was tested on amd64 using bhyve and i386, mipsel and sparc64 using QEMU. The feature still has to be tested on arm and arm64 as it wasn't possible to run FreeBSD due to the problems with QEMU emulation and lack of hardware. Designed by: def, pjd Reviewed by: cem, oshogbo, pjd Partial review: delphij, emaste, jhb, kib Approved by: pjd (mentor) Differential Revision: https://reviews.freebsd.org/D4712
2016-12-10 16:20:39 +00:00
size_t hdrsz;
int error;
#ifndef __powerpc__
if (do_minidump)
return (minidumpsys(di));
#endif
bzero(&ehdr, sizeof(ehdr));
ehdr.e_ident[EI_MAG0] = ELFMAG0;
ehdr.e_ident[EI_MAG1] = ELFMAG1;
ehdr.e_ident[EI_MAG2] = ELFMAG2;
ehdr.e_ident[EI_MAG3] = ELFMAG3;
ehdr.e_ident[EI_CLASS] = ELF_CLASS;
#if BYTE_ORDER == LITTLE_ENDIAN
ehdr.e_ident[EI_DATA] = ELFDATA2LSB;
#else
ehdr.e_ident[EI_DATA] = ELFDATA2MSB;
#endif
ehdr.e_ident[EI_VERSION] = EV_CURRENT;
ehdr.e_ident[EI_OSABI] = ELFOSABI_STANDALONE; /* XXX big picture? */
ehdr.e_type = ET_CORE;
ehdr.e_machine = EM_VALUE;
ehdr.e_phoff = sizeof(ehdr);
ehdr.e_flags = 0;
ehdr.e_ehsize = sizeof(ehdr);
ehdr.e_phentsize = sizeof(Elf_Phdr);
ehdr.e_shentsize = sizeof(Elf_Shdr);
dumpsys_pa_init();
/* Calculate dump size. */
dumpsize = 0L;
ehdr.e_phnum = dumpsys_foreach_chunk(cb_size, &dumpsize) +
DUMPSYS_NUM_AUX_HDRS;
hdrsz = ehdr.e_phoff + ehdr.e_phnum * ehdr.e_phentsize;
fileofs = MD_ALIGN(hdrsz);
dumpsize += fileofs;
hdrgap = fileofs - roundup2((off_t)hdrsz, di->blocksize);
dump_init_header(di, &kdh, KERNELDUMPMAGIC, KERNELDUMP_ARCH_VERSION,
dumpsize);
error = dump_start(di, &kdh);
if (error != 0)
goto fail;
printf("Dumping %ju MB (%d chunks)\n", (uintmax_t)dumpsize >> 20,
ehdr.e_phnum - DUMPSYS_NUM_AUX_HDRS);
/* Dump ELF header */
error = dumpsys_buf_write(di, (char*)&ehdr, sizeof(ehdr));
if (error)
goto fail;
/* Dump program headers */
error = dumpsys_foreach_chunk(cb_dumphdr, di);
if (error < 0)
goto fail;
error = dumpsys_write_aux_headers(di);
if (error < 0)
goto fail;
dumpsys_buf_flush(di);
/*
* All headers are written using blocked I/O, so we know the
* current offset is (still) block aligned. Skip the alignement
* in the file to have the segment contents aligned at page
* boundary.
*/
Add support for encrypted kernel crash dumps. Changes include modifications in kernel crash dump routines, dumpon(8) and savecore(8). A new tool called decryptcore(8) was added. A new DIOCSKERNELDUMP I/O control was added to send a kernel crash dump configuration in the diocskerneldump_arg structure to the kernel. The old DIOCSKERNELDUMP I/O control was renamed to DIOCSKERNELDUMP_FREEBSD11 for backward ABI compatibility. dumpon(8) generates an one-time random symmetric key and encrypts it using an RSA public key in capability mode. Currently only AES-256-CBC is supported but EKCD was designed to implement support for other algorithms in the future. The public key is chosen using the -k flag. The dumpon rc(8) script can do this automatically during startup using the dumppubkey rc.conf(5) variable. Once the keys are calculated dumpon sends them to the kernel via DIOCSKERNELDUMP I/O control. When the kernel receives the DIOCSKERNELDUMP I/O control it generates a random IV and sets up the key schedule for the specified algorithm. Each time the kernel tries to write a crash dump to the dump device, the IV is replaced by a SHA-256 hash of the previous value. This is intended to make a possible differential cryptanalysis harder since it is possible to write multiple crash dumps without reboot by repeating the following commands: # sysctl debug.kdb.enter=1 db> call doadump(0) db> continue # savecore A kernel dump key consists of an algorithm identifier, an IV and an encrypted symmetric key. The kernel dump key size is included in a kernel dump header. The size is an unsigned 32-bit integer and it is aligned to a block size. The header structure has 512 bytes to match the block size so it was required to make a panic string 4 bytes shorter to add a new field to the header structure. If the kernel dump key size in the header is nonzero it is assumed that the kernel dump key is placed after the first header on the dump device and the core dump is encrypted. Separate functions were implemented to write the kernel dump header and the kernel dump key as they need to be unencrypted. The dump_write function encrypts data if the kernel was compiled with the EKCD option. Encrypted kernel textdumps are not supported due to the way they are constructed which makes it impossible to use the CBC mode for encryption. It should be also noted that textdumps don't contain sensitive data by design as a user decides what information should be dumped. savecore(8) writes the kernel dump key to a key.# file if its size in the header is nonzero. # is the number of the current core dump. decryptcore(8) decrypts the core dump using a private RSA key and the kernel dump key. This is performed by a child process in capability mode. If the decryption was not successful the parent process removes a partially decrypted core dump. Description on how to encrypt crash dumps was added to the decryptcore(8), dumpon(8), rc.conf(5) and savecore(8) manual pages. EKCD was tested on amd64 using bhyve and i386, mipsel and sparc64 using QEMU. The feature still has to be tested on arm and arm64 as it wasn't possible to run FreeBSD due to the problems with QEMU emulation and lack of hardware. Designed by: def, pjd Reviewed by: cem, oshogbo, pjd Partial review: delphij, emaste, jhb, kib Approved by: pjd (mentor) Differential Revision: https://reviews.freebsd.org/D4712
2016-12-10 16:20:39 +00:00
error = dumpsys_buf_seek(di, (size_t)hdrgap);
if (error)
goto fail;
/* Dump memory chunks. */
error = dumpsys_foreach_chunk(dumpsys_cb_dumpdata, di);
if (error < 0)
goto fail;
error = dump_finish(di, &kdh);
if (error != 0)
goto fail;
printf("\nDump complete\n");
return (0);
fail:
if (error < 0)
error = -error;
if (error == ECANCELED)
printf("\nDump aborted\n");
else if (error == E2BIG || error == ENOSPC)
printf("\nDump failed. Partition too small.\n");
else
printf("\n** DUMP FAILED (ERROR %d) **\n", error);
return (error);
}
#endif