From: Kees Cook <keescook@chromium.org> stable inclusion from stable-v5.10.110 commit 9d1d8e5e42941d3a51f7cde3bee93c2b47838aaa bugzilla: https://gitee.com/openeuler/kernel/issues/I574AL Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 27e9faf415dbf94af19b9c827842435edbc1fbbc ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Yu Liao <liaoyu15@huawei.com> Reviewed-by: Wei Li <liwei391@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- scripts/gcc-plugins/stackleak_plugin.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/scripts/gcc-plugins/stackleak_plugin.c b/scripts/gcc-plugins/stackleak_plugin.c index 48e141e07956..dacd697ffd38 100644 --- a/scripts/gcc-plugins/stackleak_plugin.c +++ b/scripts/gcc-plugins/stackleak_plugin.c @@ -431,6 +431,23 @@ 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; @@ -440,13 +457,13 @@ 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; } -- 2.20.1