[PATCH iproute2] ip route: check ftell, fseek return value

[Hangbin Liu]

ftell() may return -1 in error case, which is not handled and therefore pass a
negative offset to fseek(). The return code of fseek() is also not checked.

Reported-by: Phil Sutter <p...@nwl.cc>
Signed-off-by: Hangbin Liu <liuhang...@gmail.com>
---
 ip/iproute.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/ip/iproute.c b/ip/iproute.c
index 3da23af..ba877dc 100644
--- a/ip/iproute.c
+++ b/ip/iproute.c
@@ -1859,7 +1859,11 @@ static int iproute_restore(void)
        if (route_dump_check_magic())
                exit(-1);
 
-       pos = ftell(stdin);
+       if ((pos = ftell(stdin)) == -1) {
+               perror("Failed to restore: ftell");
+               exit(errno);
+       }
+
        for (prio = 0; prio < 3; prio++) {
                int err;
 
@@ -1867,7 +1871,10 @@ static int iproute_restore(void)
                if (err)
                        exit(err);
 
-               fseek(stdin, pos, SEEK_SET);
+               if (fseek(stdin, pos, SEEK_SET) == -1) {
+                       perror("Failed to restore: fseek");
+                       exit(errno);
+               }
        }
 
        exit(0);
-- 
2.5.5