compat/pread: check initial lseek for errors
git_pread() saves the current file offset via lseek(fd, 0, SEEK_CUR) and later restores it. If the initial lseek fails (e.g., the fd is a pipe or otherwise non-seekable), current_offset is -1. This negative value is later passed to lseek(fd, -1, SEEK_SET) at line 16, which sets the file position to an unintended location (or fails with EINVAL on some platforms). Check the initial lseek return value and return -1 immediately if it fails, consistent with the error handling for the other lseek calls in the same function. Pointed out by Coverity. Assisted-by: Claude Opus 4.6 Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Johannes Schindelin committed
Jul 14, 2026 at 22:48 UTC
e7c1826ccaaf0f30bcd39b19beb478d24389137e
1 file changed
+2
compat/pread.c
+2
index 484e6d4c71..ac7d058cb8 100644
--- a/compat/pread.c
+++ b/compat/pread.c
@@ -7,6 +7,8 @@ ssize_t git_pread(int fd, void *buf, size_t count, off_t offset)
ssize_t rc;
current_offset = lseek(fd, 0, SEEK_CUR);
+ if (current_offset < 0)
+ return -1;
if (lseek(fd, offset, SEEK_SET) < 0)
return -1;