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Subject[PATCH 1/2] module: Pass struct load_info into symbol checks
Date
Since we're already using values from struct load_info, just pass this
pointer in directly and use what's needed as we need it. This allows us
to access future fields in struct load_info too.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
kernel/module.c | 22 ++++++++++------------
1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 7eba6dea4f41..ed6cf2367217 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1257,12 +1257,13 @@ static u32 resolve_rel_crc(const s32 *crc)
return *(u32 *)((void *)crc + *crc);
}

-static int check_version(Elf_Shdr *sechdrs,
- unsigned int versindex,
+static int check_version(const struct load_info *info,
const char *symname,
struct module *mod,
const s32 *crc)
{
+ Elf_Shdr *sechdrs = info->sechdrs;
+ unsigned int versindex = info->index.vers;
unsigned int i, num_versions;
struct modversion_info *versions;

@@ -1305,8 +1306,7 @@ static int check_version(Elf_Shdr *sechdrs,
return 0;
}

-static inline int check_modstruct_version(Elf_Shdr *sechdrs,
- unsigned int versindex,
+static inline int check_modstruct_version(const struct load_info *info,
struct module *mod)
{
const s32 *crc;
@@ -1322,8 +1322,8 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs,
BUG();
}
preempt_enable();
- return check_version(sechdrs, versindex,
- VMLINUX_SYMBOL_STR(module_layout), mod, crc);
+ return check_version(info, VMLINUX_SYMBOL_STR(module_layout),
+ mod, crc);
}

/* First part is kernel version, which we ignore if module has crcs. */
@@ -1337,8 +1337,7 @@ static inline int same_magic(const char *amagic, const char *bmagic,
return strcmp(amagic, bmagic) == 0;
}
#else
-static inline int check_version(Elf_Shdr *sechdrs,
- unsigned int versindex,
+static inline int check_version(const struct load_info *info,
const char *symname,
struct module *mod,
const s32 *crc)
@@ -1346,8 +1345,7 @@ static inline int check_version(Elf_Shdr *sechdrs,
return 1;
}

-static inline int check_modstruct_version(Elf_Shdr *sechdrs,
- unsigned int versindex,
+static inline int check_modstruct_version(const struct load_info *info,
struct module *mod)
{
return 1;
@@ -1383,7 +1381,7 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
if (!sym)
goto unlock;

- if (!check_version(info->sechdrs, info->index.vers, name, mod, crc)) {
+ if (!check_version(info, name, mod, crc)) {
sym = ERR_PTR(-EINVAL);
goto getname;
}
@@ -2950,7 +2948,7 @@ static struct module *setup_load_info(struct load_info *info, int flags)
info->index.pcpu = find_pcpusec(info);

/* Check module struct version now, before we try to use module. */
- if (!check_modstruct_version(info->sechdrs, info->index.vers, mod))
+ if (!check_modstruct_version(info, mod))
return ERR_PTR(-ENOEXEC);

return mod;
--
2.7.4
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