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execve: Mark exec argument buffers

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We cache mapped execve argument buffers to avoid the overhead of TLB
shootdowns.  Mark them invalid when they are freed to the cache.

MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D29460
This commit is contained in:
Mark Johnston 2021-04-13 17:40:19 -04:00
parent b261bb4057
commit f1c3adefd9
3 changed files with 8 additions and 0 deletions
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5
sys/kern/kern_exec.c
View File

@ -37,6 +37,7 @@ __FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/acct.h>
#include <sys/asan.h>
#include <sys/capsicum.h>
#include <sys/eventhandler.h>
#include <sys/exec.h>
@ -1328,6 +1329,8 @@ exec_alloc_args_kva(void **cookie)
SLIST_REMOVE_HEAD(&exec_args_kva_freelist, next);
mtx_unlock(&exec_args_kva_mtx);
}
kasan_mark((void *)argkva->addr, exec_map_entry_size,
exec_map_entry_size, 0);
*(struct exec_args_kva **)cookie = argkva;
return (argkva->addr);
}
@ -1338,6 +1341,8 @@ exec_release_args_kva(struct exec_args_kva *argkva, u_int gen)
vm_offset_t base;
base = argkva->addr;
kasan_mark((void *)argkva->addr, 0, exec_map_entry_size,
KASAN_EXEC_ARGS_FREED);
if (argkva->gen != gen) {
(void)vm_map_madvise(exec_map, base, base + exec_map_entry_size,
MADV_FREE);

2
sys/kern/subr_asan.c
View File

@ -153,6 +153,8 @@ kasan_code_name(uint8_t code)
return "UMAUseAfterFree";
case KASAN_KSTACK_FREED:
return "KernelStack";
case KASAN_EXEC_ARGS_FREED:
return "ExecKVA";
case 1 ... 7:
return "RedZonePartial";
case KASAN_STACK_LEFT:

1
sys/sys/asan.h
View File

@ -53,6 +53,7 @@
#define KASAN_KMEM_REDZONE 0xFC
#define KASAN_UMA_FREED 0xFD
#define KASAN_KSTACK_FREED 0xFE
#define KASAN_EXEC_ARGS_FREED 0xFF
void kasan_init(void);
void kasan_shadow_map(void *, size_t);