From f946cee2f81140677b89d3da334f1b3b709d1109 Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Wed, 30 Nov 2022 20:03:30 +0100 Subject: [PATCH] libiptc: Eliminate garbage access When adding a rule, valgrind prints: Syscall param socketcall.setsockopt(optval) points to uninitialised byte(s) at 0x4A8165A: setsockopt (in /lib64/libc.so.6) by 0x4857A48: iptc_commit (libiptc.c:2676) by 0x10E4BB: iptables_main (iptables-standalone.c:61) by 0x49A3349: (below main) (in /lib64/libc.so.6) Address 0x4b63788 is 40 bytes inside a block of size 1,448 alloc'd at 0x484659F: calloc (vg_replace_malloc.c:1328) by 0x4857654: iptc_commit (libiptc.c:2564) by 0x10E4BB: iptables_main (iptables-standalone.c:61) by 0x49A3349: (below main) (in /lib64/libc.so.6) This is because repl->counters is not initialized upon allocation. Since the field is an array, make use of calloc() which implicitly does the initialization. Fixes: e37c0dc100c51 ("Revert the recent addition of memset()'s to TC_COMMIT. One of them is bogus and the other one needs more investigation to why valgrind is complaining.") Signed-off-by: Phil Sutter (cherry picked from commit 39a2aa8cbfc99f4a75dfc0786a80ced90952ab29) --- libiptc/libiptc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/libiptc/libiptc.c b/libiptc/libiptc.c index 56bb75e5c3bef..157fbc4b72ebc 100644 --- a/libiptc/libiptc.c +++ b/libiptc/libiptc.c @@ -2554,8 +2554,8 @@ TC_COMMIT(struct xtc_handle *handle) + sizeof(STRUCT_COUNTERS) * new_number; /* These are the old counters we will get from kernel */ - repl->counters = malloc(sizeof(STRUCT_COUNTERS) - * handle->info.num_entries); + repl->counters = calloc(handle->info.num_entries, + sizeof(STRUCT_COUNTERS)); if (!repl->counters) { errno = ENOMEM; goto out_free_repl; -- 2.40.0