Attempting to compile pacman with gcc8 results in several warnings like:
remove.c: In function ‘unlink_file.isra.4’:
remove.c:407:34: warning: ‘.pacsave.’ directive output may be truncated writing 9 bytes into a region of size between 1 and 4096 [-Wformat-truncation=]
Fix by adding checks to error out if snprintf tries to reserve a
truncated filename. Because the return values are checked, gcc delegates
the truncation response to our code instead of throwing warnings.
Signed-off-by: Eli Schwartz <eschwartz(a)archlinux.org>
---
This seems to solve the issue, though as mentioned in IRC it might be
nice if we only needed to check the first use of newfile -- everything
else is guaranteed to be shorter.
Also feel free to nitpick the log message wording.
lib/libalpm/remove.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/lib/libalpm/remove.c b/lib/libalpm/remove.c
index 5b53ac34..78ca5be7 100644
--- a/lib/libalpm/remove.c
+++ b/lib/libalpm/remove.c
@@ -404,14 +404,22 @@ static void shift_pacsave(alpm_handle_t *handle, const char *file)
/* Shift pacsaves */
unsigned long i;
for(i = log_max + 1; i > 1; i--) {
- snprintf(oldfile, PATH_MAX, "%s.pacsave.%lu", file, i-1);
- snprintf(newfile, PATH_MAX, "%s.pacsave.%lu", file, i);
+ if(snprintf(oldfile, PATH_MAX, "%s.pacsave.%lu", file, i-1) >= PATH_MAX
+ || snprintf(newfile, PATH_MAX, "%s.pacsave.%lu", file, i) >= PATH_MAX) {
+ _alpm_log(handle, ALPM_LOG_ERROR,
+ _("could not backup %s due to PATH_MAX overflow\n"), file);
+ goto cleanup;
+ }
rename(oldfile, newfile);
}
- snprintf(oldfile, PATH_MAX, "%s.pacsave", file);
+ if(snprintf(oldfile, PATH_MAX, "%s.pacsave", file) >= PATH_MAX
+ || snprintf(newfile, PATH_MAX, "%s.1", oldfile) >= PATH_MAX) {
+ _alpm_log(handle, ALPM_LOG_ERROR,
+ _("could not backup %s due to PATH_MAX overflow\n"), file);
+ goto cleanup;
+ }
if(stat(oldfile, &st) == 0) {
- snprintf(newfile, PATH_MAX, "%s.1", oldfile);
rename(oldfile, newfile);
}
--
2.17.0