Check lseek() for failure

Error: CHECKED_RETURN (CWE-252): [#def26]
libslirp-4.3.0/src/tftp.c:121: check_return: Calling "lseek(spt->fd, block_nr * spt->block_size, 0)" without checking return value. This library function may fail and return an error code.
  119|
  120|       if (len) {
  121|->         lseek(spt->fd, block_nr * spt->block_size, SEEK_SET);
  122|
  123|           bytes_read = read(spt->fd, buf, len);

Signed-off-by: Jindrich Novy <jnovy@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/src/tftp.c b/src/tftp.c
index c209145..c6950ee 100644
--- a/src/tftp.c
+++ b/src/tftp.c
@@ -118,7 +118,9 @@ static int tftp_read_data(struct tftp_session *spt, uint32_t block_nr,
     }
 
     if (len) {
-        lseek(spt->fd, block_nr * spt->block_size, SEEK_SET);
+        if (lseek(spt->fd, block_nr * spt->block_size, SEEK_SET) == (off_t)-1) {
+            return -1;
+        }
 
         bytes_read = read(spt->fd, buf, len);
     }