From 04211a574641e29b529dcc84e75c03d7e9e368cf Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Thu, 4 Feb 2016 13:05:02 +0000 Subject: MIPS: Bail on unsupported module relocs 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 Cc: James Hogan Cc: Steven J. Hill Cc: Andrey Ryabinin Cc: Andrew Morton 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 --- arch/mips/kernel/module-rela.c | 19 ++++++++++++++++--- arch/mips/kernel/module.c | 19 ++++++++++++++++--- 2 files changed, 32 insertions(+), 6 deletions(-) (limited to 'arch') diff --git a/arch/mips/kernel/module-rela.c b/arch/mips/kernel/module-rela.c index 2b70723071c3..9083d63b765c 100644 --- a/arch/mips/kernel/module-rela.c +++ b/arch/mips/kernel/module-rela.c @@ -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]); + + if (type < ARRAY_SIZE(reloc_handlers_rela)) + handler = reloc_handlers_rela[type]; + else + handler = NULL; - res = reloc_handlers_rela[ELF_MIPS_R_TYPE(rel[i])](me, location, v); + 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; } diff --git a/arch/mips/kernel/module.c b/arch/mips/kernel/module.c index 1833f5171ccd..f9b2936d598d 100644 --- a/arch/mips/kernel/module.c +++ b/arch/mips/kernel/module.c @@ -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]); + + if (type < ARRAY_SIZE(reloc_handlers_rel)) + handler = reloc_handlers_rel[type]; + else + handler = NULL; - res = reloc_handlers_rel[ELF_MIPS_R_TYPE(rel[i])](me, location, v); + 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; } -- cgit v1.2.3