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| author | Kees Cook <keescook@chromium.org> | 2022-02-06 18:08:20 +0100 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2022-02-06 19:55:03 +0100 |
| commit | 27e9faf415dbf94af19b9c827842435edbc1fbbc (patch) | |
| tree | 918848ab170d5af3f4efb9b2def57b8e1a7d545e /scripts/gcc-plugins | |
| parent | gcc-plugins/stackleak: Provide verbose mode (diff) | |
| download | linux-27e9faf415dbf94af19b9c827842435edbc1fbbc.tar.xz linux-27e9faf415dbf94af19b9c827842435edbc1fbbc.zip | |
gcc-plugins/stackleak: Exactly match strings instead of prefixes
Since STRING_CST may not be NUL terminated, strncmp() was used for check
for equality. However, this may lead to mismatches for longer section
names where the start matches the tested-for string. Test for exact
equality by checking for the presences of NUL termination.
Cc: Alexander Popov <alex.popov@linux.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'scripts/gcc-plugins')
| -rw-r--r-- | scripts/gcc-plugins/stackleak_plugin.c | 25 |
1 files changed, 21 insertions, 4 deletions
diff --git a/scripts/gcc-plugins/stackleak_plugin.c b/scripts/gcc-plugins/stackleak_plugin.c index e9db7dcb3e5f..b04aa8e91a41 100644 --- a/scripts/gcc-plugins/stackleak_plugin.c +++ b/scripts/gcc-plugins/stackleak_plugin.c @@ -429,6 +429,23 @@ static unsigned int stackleak_cleanup_execute(void) return 0; } +/* + * STRING_CST may or may not be NUL terminated: + * https://gcc.gnu.org/onlinedocs/gccint/Constant-expressions.html + */ +static inline bool string_equal(tree node, const char *string, int length) +{ + if (TREE_STRING_LENGTH(node) < length) + return false; + if (TREE_STRING_LENGTH(node) > length + 1) + return false; + if (TREE_STRING_LENGTH(node) == length + 1 && + TREE_STRING_POINTER(node)[length] != '\0') + return false; + return !memcmp(TREE_STRING_POINTER(node), string, length); +} +#define STRING_EQUAL(node, str) string_equal(node, str, strlen(str)) + static bool stackleak_gate(void) { tree section; @@ -438,13 +455,13 @@ static bool stackleak_gate(void) if (section && TREE_VALUE(section)) { section = TREE_VALUE(TREE_VALUE(section)); - if (!strncmp(TREE_STRING_POINTER(section), ".init.text", 10)) + if (STRING_EQUAL(section, ".init.text")) return false; - if (!strncmp(TREE_STRING_POINTER(section), ".devinit.text", 13)) + if (STRING_EQUAL(section, ".devinit.text")) return false; - if (!strncmp(TREE_STRING_POINTER(section), ".cpuinit.text", 13)) + if (STRING_EQUAL(section, ".cpuinit.text")) return false; - if (!strncmp(TREE_STRING_POINTER(section), ".meminit.text", 13)) + if (STRING_EQUAL(section, ".meminit.text")) return false; } |