| From a97777889328157bb7d06ec618bad16712a9c345 Mon Sep 17 00:00:00 2001 |
| From: Denys Vlasenko <vda.linux@googlemail.com> |
| Date: Tue, 3 Feb 2015 12:11:30 +0100 |
| Subject: [PATCH] ifconfig: fix double free fatal error in INET_sprint |
| |
| Derived from: |
| http://git.busybox.net/busybox/commit/?id=a97777889328157bb7d06ec618bad16712a9c345. |
| |
| While INET_sprint or INET6_sprint is called circularly by keeping |
| ifconfiging, sap->sa_family would be cleaned by other parallel processes |
| such as dhclient sometimes, and then there would be a double free error |
| like the following: |
| |
| *** glibc detected *** ifconfig: double free or corruption (fasttop): 0x000a6008 *** |
| ======= Backtrace: ========= |
| /lib/libc.so.6(+0x6bc84)[0x40133c84] |
| /lib/libc.so.6(cfree+0x94)[0x40138684] |
| ifconfig[0x1c460] |
| ifconfig[0x1c6a0] |
| ifconfig[0x1ccf4] |
| ifconfig[0x187c8] |
| ifconfig[0xd544] |
| ifconfig[0xd5dc] |
| ifconfig[0xdca8] |
| /lib/libc.so.6(__libc_start_main+0x110)[0x400df258] |
| ======= Memory map: ======== |
| 00008000-0009c000 r-xp 00000000 1f:05 444328 /bin/busybox |
| 000a3000-000a4000 rw-p 00093000 1f:05 444328 /bin/busybox |
| |
| This patch moved free() two lines down to address this problem. |
| |
| Upstream-Status: Backport |
| |
| Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> |
| --- |
| networking/interface.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| diff --git a/networking/interface.c b/networking/interface.c |
| index bf7d2b1..b0572d0 100644 |
| --- a/networking/interface.c |
| +++ b/networking/interface.c |
| @@ -91,9 +91,9 @@ static const char* FAST_FUNC INET_sprint(struct sockaddr *sap, int numeric) |
| { |
| static char *buff; /* defaults to NULL */ |
| |
| - free(buff); |
| if (sap->sa_family == 0xFFFF || sap->sa_family == 0) |
| return "[NONE SET]"; |
| + free(buff); |
| buff = INET_rresolve((struct sockaddr_in *) sap, numeric, 0xffffff00); |
| return buff; |
| } |
| @@ -173,9 +173,9 @@ static const char* FAST_FUNC INET6_sprint(struct sockaddr *sap, int numeric) |
| { |
| static char *buff; |
| |
| - free(buff); |
| if (sap->sa_family == 0xFFFF || sap->sa_family == 0) |
| return "[NONE SET]"; |
| + free(buff); |
| buff = INET6_rresolve((struct sockaddr_in6 *) sap, numeric); |
| return buff; |
| } |
| -- |
| 1.8.3.4 |
| |