loader: fix endianness conversion

r328536 broke symbol loading on amd64 at least (and probably other
arches). r328826 contained the problem to ppc only by adding
pre-processors guards.

Fix this properly by moving the endianness conversion to separate
helper functions, and make the conversion more robust by using sizeof
instead of having to manually code the size of each field.

Finally list the fields in each structure in a macro in order to avoid
code repetition.

Sponsored by:		Citrix Systems R&D
Reviewed by:		kib emaste wma
Differential revision:	https://reviews.freebsd.org/D14267
This commit is contained in:
Roger Pau Monné 2018-02-09 10:20:16 +00:00
parent f7d3578564
commit 12363d8ea3
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=329060

View File

@ -87,6 +87,112 @@ const char *__elfN(moduletype) = "elf module";
u_int64_t __elfN(relocation_offset) = 0;
extern void elf_wrong_field_size(void);
#define CONVERT_FIELD(b, f, e) \
switch (sizeof((b)->f)) { \
case 2: \
(b)->f = e ## 16toh((b)->f); \
break; \
case 4: \
(b)->f = e ## 32toh((b)->f); \
break; \
case 8: \
(b)->f = e ## 64toh((b)->f); \
break; \
default: \
/* Force a link time error. */ \
elf_wrong_field_size(); \
break; \
}
#define CONVERT_SWITCH(h, d, f) \
switch ((h)->e_ident[EI_DATA]) { \
case ELFDATA2MSB: \
f(d, be); \
break; \
case ELFDATA2LSB: \
f(d, le); \
break; \
default: \
return (EINVAL); \
}
static int elf_header_convert(Elf_Ehdr *ehdr)
{
/*
* Fixup ELF header endianness.
*
* The Xhdr structure was loaded using block read call to optimize file
* accesses. It might happen, that the endianness of the system memory
* is different that endianness of the ELF header. Swap fields here to
* guarantee that Xhdr always contain valid data regardless of
* architecture.
*/
#define HEADER_FIELDS(b, e) \
CONVERT_FIELD(b, e_type, e); \
CONVERT_FIELD(b, e_machine, e); \
CONVERT_FIELD(b, e_version, e); \
CONVERT_FIELD(b, e_entry, e); \
CONVERT_FIELD(b, e_phoff, e); \
CONVERT_FIELD(b, e_shoff, e); \
CONVERT_FIELD(b, e_flags, e); \
CONVERT_FIELD(b, e_ehsize, e); \
CONVERT_FIELD(b, e_phentsize, e); \
CONVERT_FIELD(b, e_phnum, e); \
CONVERT_FIELD(b, e_shentsize, e); \
CONVERT_FIELD(b, e_shnum, e); \
CONVERT_FIELD(b, e_shstrndx, e)
CONVERT_SWITCH(ehdr, ehdr, HEADER_FIELDS);
#undef HEADER_FIELDS
return (0);
}
static int elf_program_header_convert(const Elf_Ehdr *ehdr, Elf_Phdr *phdr)
{
#define PROGRAM_HEADER_FIELDS(b, e) \
CONVERT_FIELD(b, p_type, e); \
CONVERT_FIELD(b, p_flags, e); \
CONVERT_FIELD(b, p_offset, e); \
CONVERT_FIELD(b, p_vaddr, e); \
CONVERT_FIELD(b, p_paddr, e); \
CONVERT_FIELD(b, p_filesz, e); \
CONVERT_FIELD(b, p_memsz, e); \
CONVERT_FIELD(b, p_align, e)
CONVERT_SWITCH(ehdr, phdr, PROGRAM_HEADER_FIELDS);
#undef PROGRAM_HEADER_FIELDS
return (0);
}
static int elf_section_header_convert(const Elf_Ehdr *ehdr, Elf_Shdr *shdr)
{
#define SECTION_HEADER_FIELDS(b, e) \
CONVERT_FIELD(b, sh_name, e); \
CONVERT_FIELD(b, sh_type, e); \
CONVERT_FIELD(b, sh_link, e); \
CONVERT_FIELD(b, sh_info, e); \
CONVERT_FIELD(b, sh_flags, e); \
CONVERT_FIELD(b, sh_addr, e); \
CONVERT_FIELD(b, sh_offset, e); \
CONVERT_FIELD(b, sh_size, e); \
CONVERT_FIELD(b, sh_addralign, e); \
CONVERT_FIELD(b, sh_entsize, e)
CONVERT_SWITCH(ehdr, shdr, SECTION_HEADER_FIELDS);
#undef SECTION_HEADER_FIELDS
return (0);
}
#undef CONVERT_SWITCH
#undef CONVERT_FIELD
static int
__elfN(load_elf_header)(char *filename, elf_file_t ef)
{
@ -127,62 +233,9 @@ __elfN(load_elf_header)(char *filename, elf_file_t ef)
goto error;
}
#ifdef __powerpc__
/*
* XXX: should be in a separate helper.
*
* Fixup ELF endianness.
*
* The Xhdr structure was loaded using block read call to
* optimize file accesses. It might happen, that the endianness
* of the system memory is different that endianness of
* the ELF header.
* Swap fields here to guarantee that Xhdr always contain
* valid data regardless of architecture.
*/
if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) {
ehdr->e_type = be16toh(ehdr->e_type);
ehdr->e_machine = be16toh(ehdr->e_machine);
ehdr->e_version = be32toh(ehdr->e_version);
if (ehdr->e_ident[EI_CLASS] == ELFCLASS64) {
ehdr->e_entry = be64toh(ehdr->e_entry);
ehdr->e_phoff = be64toh(ehdr->e_phoff);
ehdr->e_shoff = be64toh(ehdr->e_shoff);
} else {
ehdr->e_entry = be32toh(ehdr->e_entry);
ehdr->e_phoff = be32toh(ehdr->e_phoff);
ehdr->e_shoff = be32toh(ehdr->e_shoff);
}
ehdr->e_flags = be32toh(ehdr->e_flags);
ehdr->e_ehsize = be16toh(ehdr->e_ehsize);
ehdr->e_phentsize = be16toh(ehdr->e_phentsize);
ehdr->e_phnum = be16toh(ehdr->e_phnum);
ehdr->e_shentsize = be16toh(ehdr->e_shentsize);
ehdr->e_shnum = be16toh(ehdr->e_shnum);
ehdr->e_shstrndx = be16toh(ehdr->e_shstrndx);
} else {
ehdr->e_type = le16toh(ehdr->e_type);
ehdr->e_machine = le16toh(ehdr->e_machine);
ehdr->e_version = le32toh(ehdr->e_version);
if (ehdr->e_ident[EI_CLASS] == ELFCLASS64) {
ehdr->e_entry = le64toh(ehdr->e_entry);
ehdr->e_phoff = le64toh(ehdr->e_phoff);
ehdr->e_shoff = le64toh(ehdr->e_shoff);
} else {
ehdr->e_entry = le32toh(ehdr->e_entry);
ehdr->e_phoff = le32toh(ehdr->e_phoff);
ehdr->e_shoff = le32toh(ehdr->e_shoff);
}
ehdr->e_flags = le32toh(ehdr->e_flags);
ehdr->e_ehsize = le16toh(ehdr->e_ehsize);
ehdr->e_phentsize = le16toh(ehdr->e_phentsize);
ehdr->e_phnum = le16toh(ehdr->e_phnum);
ehdr->e_shentsize = le16toh(ehdr->e_shentsize);
ehdr->e_shnum = le16toh(ehdr->e_shnum);
ehdr->e_shstrndx = le16toh(ehdr->e_shstrndx);
}
#endif
err = elf_header_convert(ehdr);
if (err)
goto error;
if (ehdr->e_version != EV_CURRENT || ehdr->e_machine != ELF_TARG_MACH) { /* Machine ? */
err = EFTYPE;
@ -453,57 +506,8 @@ __elfN(loadimage)(struct preloaded_file *fp, elf_file_t ef, u_int64_t off)
phdr = (Elf_Phdr *)(ef->firstpage + ehdr->e_phoff);
for (i = 0; i < ehdr->e_phnum; i++) {
#ifdef __powerpc__
/*
* XXX: should be in a seprate helper.
*
* Fixup ELF endianness.
*
* The Xhdr structure was loaded using block read call to
* optimize file accesses. It might happen, that the endianness
* of the system memory is different that endianness of
* the ELF header.
* Swap fields here to guarantee that Xhdr always contain
* valid data regardless of architecture.
*/
if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) {
phdr[i].p_type = be32toh(phdr[i].p_type);
phdr[i].p_flags = be32toh(phdr[i].p_flags);
if (ehdr->e_ident[EI_CLASS] == ELFCLASS64) {
phdr[i].p_offset = be64toh(phdr[i].p_offset);
phdr[i].p_vaddr = be64toh(phdr[i].p_vaddr);
phdr[i].p_paddr = be64toh(phdr[i].p_paddr);
phdr[i].p_filesz = be64toh(phdr[i].p_filesz);
phdr[i].p_memsz = be64toh(phdr[i].p_memsz);
phdr[i].p_align = be64toh(phdr[i].p_align);
} else {
phdr[i].p_offset = be32toh(phdr[i].p_offset);
phdr[i].p_vaddr = be32toh(phdr[i].p_vaddr);
phdr[i].p_paddr = be32toh(phdr[i].p_paddr);
phdr[i].p_filesz = be32toh(phdr[i].p_filesz);
phdr[i].p_memsz = be32toh(phdr[i].p_memsz);
phdr[i].p_align = be32toh(phdr[i].p_align);
}
} else {
phdr[i].p_type = le32toh(phdr[i].p_type);
phdr[i].p_flags = le32toh(phdr[i].p_flags);
if (ehdr->e_ident[EI_CLASS] == ELFCLASS64) {
phdr[i].p_offset = le64toh(phdr[i].p_offset);
phdr[i].p_vaddr = le64toh(phdr[i].p_vaddr);
phdr[i].p_paddr = le64toh(phdr[i].p_paddr);
phdr[i].p_filesz = le64toh(phdr[i].p_filesz);
phdr[i].p_memsz = le64toh(phdr[i].p_memsz);
phdr[i].p_align = le64toh(phdr[i].p_align);
} else {
phdr[i].p_offset = le32toh(phdr[i].p_offset);
phdr[i].p_vaddr = le32toh(phdr[i].p_vaddr);
phdr[i].p_paddr = le32toh(phdr[i].p_paddr);
phdr[i].p_filesz = le32toh(phdr[i].p_filesz);
phdr[i].p_memsz = le32toh(phdr[i].p_memsz);
phdr[i].p_align = le32toh(phdr[i].p_align);
}
}
#endif
if (elf_program_header_convert(ehdr, phdr))
continue;
/* We want to load PT_LOAD segments only.. */
if (phdr[i].p_type != PT_LOAD)
@ -580,63 +584,8 @@ __elfN(loadimage)(struct preloaded_file *fp, elf_file_t ef, u_int64_t off)
goto nosyms;
}
#ifdef __powerpc__
/*
* XXX: should be in a seprate helper.
*
* Fixup ELF endianness.
*
* The Xhdr structure was loaded using block read call to
* optimize file accesses. It might happen, that the endianness
* of the system memory is different that endianness of
* the ELF header.
* Swap fields here to guarantee that Xhdr always contain
* valid data regardless of architecture.
*/
for (i = 0; i < ehdr->e_shnum; i++) {
if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) {
shdr[i].sh_name = be32toh(shdr[i].sh_name);
shdr[i].sh_type = be32toh(shdr[i].sh_type);
shdr[i].sh_link = be32toh(shdr[i].sh_link);
shdr[i].sh_info = be32toh(shdr[i].sh_info);
if (ehdr->e_ident[EI_CLASS] == ELFCLASS64) {
shdr[i].sh_flags = be64toh(shdr[i].sh_flags);
shdr[i].sh_addr = be64toh(shdr[i].sh_addr);
shdr[i].sh_offset = be64toh(shdr[i].sh_offset);
shdr[i].sh_size = be64toh(shdr[i].sh_size);
shdr[i].sh_addralign = be64toh(shdr[i].sh_addralign);
shdr[i].sh_entsize = be64toh(shdr[i].sh_entsize);
} else {
shdr[i].sh_flags = be32toh(shdr[i].sh_flags);
shdr[i].sh_addr = be32toh(shdr[i].sh_addr);
shdr[i].sh_offset = be32toh(shdr[i].sh_offset);
shdr[i].sh_size = be32toh(shdr[i].sh_size);
shdr[i].sh_addralign = be32toh(shdr[i].sh_addralign);
shdr[i].sh_entsize = be32toh(shdr[i].sh_entsize);
}
} else {
shdr[i].sh_name = le32toh(shdr[i].sh_name);
shdr[i].sh_type = le32toh(shdr[i].sh_type);
shdr[i].sh_link = le32toh(shdr[i].sh_link);
shdr[i].sh_info = le32toh(shdr[i].sh_info);
if (ehdr->e_ident[EI_CLASS] == ELFCLASS64) {
shdr[i].sh_flags = le64toh(shdr[i].sh_flags);
shdr[i].sh_addr = le64toh(shdr[i].sh_addr);
shdr[i].sh_offset = le64toh(shdr[i].sh_offset);
shdr[i].sh_size = le64toh(shdr[i].sh_size);
shdr[i].sh_addralign = le64toh(shdr[i].sh_addralign);
shdr[i].sh_entsize = le64toh(shdr[i].sh_entsize);
} else {
shdr[i].sh_flags = le32toh(shdr[i].sh_flags);
shdr[i].sh_addr = le32toh(shdr[i].sh_addr);
shdr[i].sh_offset = le32toh(shdr[i].sh_offset);
shdr[i].sh_size = le32toh(shdr[i].sh_size);
shdr[i].sh_addralign = le32toh(shdr[i].sh_addralign);
shdr[i].sh_entsize = le32toh(shdr[i].sh_entsize);
}
}
}
#endif
for (i = 0; i < ehdr->e_shnum; i++)
elf_section_header_convert(ehdr, &shdr[i]);
file_addmetadata(fp, MODINFOMD_SHDR, chunk, shdr);