From: Dave Reisner Date: Tue, 17 Sep 2013 21:05:09 +0000 (-0400) Subject: libmount: use memmove when overlap possible X-Git-Tag: v2.24-rc1~73 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4e9f59d1ee293108cd1d577f7b1a182f5b0ac9c0;p=thirdparty%2Futil-linux.git libmount: use memmove when overlap possible When unmounting some mountpoints as an unprivileged user (via the 'user' option in fstab), the umount fails. Debug output of 'umount /opt' reveals: 17760: libmount: CXT: [0x22890e0]: do umount 17760: libmount: UTILS: moving to /opt parent 17760: libmount: CXT: current directory moved to / [last_component='opt'] 17760: libmount: CXT: [0x22890e0]: umount(2) [target='pt', flags=0x00000000] valgrind shows the problem: ==23544== Source and destination overlap in memcpy(0x58d1370, 0x58d1371, 4) ==23544== at 0x4C2BBC3: memcpy@@GLIBC_2.14 (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so) ==23544== by 0x4E537C3: mnt_chdir_to_parent (utils.c:168) ==23544== by 0x4E45E4C: mnt_context_do_umount (context_umount.c:601) ==23544== by 0x4E46513: mnt_context_umount (context_umount.c:855) ==23544== by 0x403476: umount_one (umount.c:299) ==23544== by 0x402B34: main (umount.c:629) ==23544== ref: https://bugs.archlinux.org/task/36968 Signed-off-by: Dave Reisner --- diff --git a/libmount/src/utils.c b/libmount/src/utils.c index 9f992412f4..3cab936441 100644 --- a/libmount/src/utils.c +++ b/libmount/src/utils.c @@ -165,7 +165,7 @@ int mnt_chdir_to_parent(const char *target, char **filename) if (!last || !*last) memcpy(*filename, ".", 2); else - memcpy(*filename, last, strlen(last) + 1); + memmove(*filename, last, strlen(last) + 1); } else free(buf); return 0;