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MIPS: Bail on unsupported module relocs

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When an unsupported reloc is encountered in a module, we currently
blindly branch to whatever would be at its entry in the reloc handler
function pointer arrays. This may be NULL, or if the unsupported reloc
has a type greater than that of the supported reloc with the highest
type then we'll dereference some value after the function pointer array
& branch to that. The result is at best a kernel oops.

Fix this by checking that the reloc type has an entry in the function
pointer array (ie. is less than the number of items in the array) and
that the handler is non-NULL, returning an error code to fail the module
load if no handler is found.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/12432/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Paul Burton 2016-02-04 13:05:02 +00:00 committed by Ralf Baechle
parent f7f797cfc6
commit 04211a5746
2 changed files with 32 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
arch/mips/kernel/module-rela.c
View File

@ -109,9 +109,10 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
struct module *me)
{
Elf_Mips_Rela *rel = (void *) sechdrs[relsec].sh_addr;
int (*handler)(struct module *me, u32 *location, Elf_Addr v);
Elf_Sym *sym;
u32 *location;
unsigned int i;
unsigned int i, type;
Elf_Addr v;
int res;
@ -134,9 +135,21 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
return -ENOENT;
}
v = sym->st_value + rel[i].r_addend;
type = ELF_MIPS_R_TYPE(rel[i]);
res = reloc_handlers_rela[ELF_MIPS_R_TYPE(rel[i])](me, location, v);
if (type < ARRAY_SIZE(reloc_handlers_rela))
handler = reloc_handlers_rela[type];
else
handler = NULL;
if (!handler) {
pr_err("%s: Unknown relocation type %u\n",
me->name, type);
return -EINVAL;
}
v = sym->st_value + rel[i].r_addend;
res = handler(me, location, v);
if (res)
return res;
}

19
arch/mips/kernel/module.c
View File

@ -197,9 +197,10 @@ int apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
struct module *me)
{
Elf_Mips_Rel *rel = (void *) sechdrs[relsec].sh_addr;
int (*handler)(struct module *me, u32 *location, Elf_Addr v);
Elf_Sym *sym;
u32 *location;
unsigned int i;
unsigned int i, type;
Elf_Addr v;
int res;
@ -223,9 +224,21 @@ int apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
return -ENOENT;
}
v = sym->st_value;
type = ELF_MIPS_R_TYPE(rel[i]);
res = reloc_handlers_rel[ELF_MIPS_R_TYPE(rel[i])](me, location, v);
if (type < ARRAY_SIZE(reloc_handlers_rel))
handler = reloc_handlers_rel[type];
else
handler = NULL;
if (!handler) {
pr_err("%s: Unknown relocation type %u\n",
me->name, type);
return -EINVAL;
}
v = sym->st_value;
res = handler(me, location, v);
if (res)
return res;
}