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author | 2022-05-24 01:46:22 +0900 | |
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committer | 2022-05-27 16:07:44 +0900 | |
commit | d6b732666a1bae0df3c3ae06925043bba34502b1 (patch) | |
tree | e9fad3eb40a8b359ddb489843baf410793310749 /scripts/mod | |
parent | modpost: fix removing numeric suffixes (diff) | |
download | linux-d6b732666a1bae0df3c3ae06925043bba34502b1.tar.gz linux-d6b732666a1bae0df3c3ae06925043bba34502b1.tar.bz2 linux-d6b732666a1bae0df3c3ae06925043bba34502b1.zip |
modpost: fix undefined behavior of is_arm_mapping_symbol()
The return value of is_arm_mapping_symbol() is unpredictable when "$"
is passed in.
strchr(3) says:
The strchr() and strrchr() functions return a pointer to the matched
character or NULL if the character is not found. The terminating null
byte is considered part of the string, so that if c is specified as
'\0', these functions return a pointer to the terminator.
When str[1] is '\0', strchr("axtd", str[1]) is not NULL, and str[2] is
referenced (i.e. buffer overrun).
Test code
---------
char str1[] = "abc";
char str2[] = "ab";
strcpy(str1, "$");
strcpy(str2, "$");
printf("test1: %d\n", is_arm_mapping_symbol(str1));
printf("test2: %d\n", is_arm_mapping_symbol(str2));
Result
------
test1: 0
test2: 1
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Diffstat (limited to 'scripts/mod')
-rw-r--r-- | scripts/mod/modpost.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 08f6989437bd..1092906867f0 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1180,7 +1180,8 @@ static int secref_whitelist(const struct sectioncheck *mismatch, static inline int is_arm_mapping_symbol(const char *str) { - return str[0] == '$' && strchr("axtd", str[1]) + return str[0] == '$' && + (str[1] == 'a' || str[1] == 'd' || str[1] == 't' || str[1] == 'x') && (str[2] == '\0' || str[2] == '.'); } |