On 9/18/19 5:04 PM, Nicolas Iooss wrote:
When compile_regex() calls regex_prepare_data() and this function fails
in the following condition:
*regex = regex_data_create();
if (!(*regex))
return -1;
... error_data has been zero-ed and compile_regex() calls:
regex_format_error(&error_data,
regex_error_format_buffer,
sizeof(regex_error_format_buffer));
This leads to a call to strlen(error_data->error_buffer), where
error_data->error_buffer is NULL.
Avoid this by checking that error_data->error_buffer is not NULL before
calling strlen().
It seems like regex_format_error() should just return immediately if
!error_data->error_code (#ifdef USE_PCRE2) or !error_data->error_buffer
(#ifndef USE_PCRE2), since there is no back-end error message to get and
report in that situation.
This issue has been found using clang's static analyzer:
https://337-118970575-gh.circle-artifacts.com/0/output-scan-build/2019-09-01-181851-6152-1/report-0b122b.html#EndPath
Signed-off-by: Nicolas Iooss <nicolas.iooss@xxxxxxx>
---
libselinux/src/regex.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libselinux/src/regex.c b/libselinux/src/regex.c
index a6fcbbfec1f3..f967efe4a32f 100644
--- a/libselinux/src/regex.c
+++ b/libselinux/src/regex.c
@@ -546,7 +546,7 @@ void regex_format_error(struct regex_error_data const *error_data, char *buffer,
if (rc < 0)
abort();
- if ((size_t)rc < strlen(error_data->error_buffer))
+ if (error_data->error_buffer && (size_t)rc < strlen(error_data->error_buffer))
goto truncated;
#endif
