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modpost: validate symbol names also in find_elf_symbol 

If an ARM mapping symbol shares an address with a valid symbol,
find_elf_symbol can currently return the mapping symbol instead, as the
symbol is not validated. This can result in confusing warnings:

  WARNING: vmlinux.o(.text+0x18f4028): Section mismatch in reference
  from the function set_reset_devices() to the variable .init.text:$x.0

This change adds a call to is_valid_name to find_elf_symbol, similarly
to how it's already used in find_elf_symbol2.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
This commit is contained in:
Sami Tolvanen 2018-10-23 15:15:35 -07:00 committed by Masahiro Yamada
parent 813af51f5d
commit 5818c683a6
1 changed files with 26 additions and 24 deletions
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50
scripts/mod/modpost.c
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@ -1204,6 +1204,30 @@ static int secref_whitelist(const struct sectioncheck *mismatch,
return 1;
}
static inline int is_arm_mapping_symbol(const char *str)
{
return str[0] == '$' && strchr("axtd", str[1])
&& (str[2] == '\0' || str[2] == '.');
}
/*
* If there's no name there, ignore it; likewise, ignore it if it's
* one of the magic symbols emitted used by current ARM tools.
*
* Otherwise if find_symbols_between() returns those symbols, they'll
* fail the whitelist tests and cause lots of false alarms ... fixable
* only by merging __exit and __init sections into __text, bloating
* the kernel (which is especially evil on embedded platforms).
*/
static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
{
const char *name = elf->strtab + sym->st_name;
if (!name || !strlen(name))
return 0;
return !is_arm_mapping_symbol(name);
}
/**
* Find symbol based on relocation record info.
* In some cases the symbol supplied is a valid symbol so
@ -1229,6 +1253,8 @@ static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
continue;
if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
continue;
if (!is_valid_name(elf, sym))
continue;
if (sym->st_value == addr)
return sym;
/* Find a symbol nearby - addr are maybe negative */
@ -1247,30 +1273,6 @@ static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
return NULL;
}
static inline int is_arm_mapping_symbol(const char *str)
{
return str[0] == '$' && strchr("axtd", str[1])
&& (str[2] == '\0' || str[2] == '.');
}
/*
* If there's no name there, ignore it; likewise, ignore it if it's
* one of the magic symbols emitted used by current ARM tools.
*
* Otherwise if find_symbols_between() returns those symbols, they'll
* fail the whitelist tests and cause lots of false alarms ... fixable
* only by merging __exit and __init sections into __text, bloating
* the kernel (which is especially evil on embedded platforms).
*/
static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
{
const char *name = elf->strtab + sym->st_name;
if (!name || !strlen(name))
return 0;
return !is_arm_mapping_symbol(name);
}
/*
* Find symbols before or equal addr and after addr - in the section sec.
* If we find two symbols with equal offset prefer one with a valid name.