Re: [Crash-utility] [PATCH 2/2] tools: fix potential source and destination overlap with strcpy()

valgrind detects the following error: ==14603== Source and destination overlap in strcpy(0x1ffefffe42, 0x1ffefffe44) ==14603== at 0x483CD70: strcpy (vg_replace_strmem.c:511) ==14603== by 0x477813: pages_to_size (tools.c:6393) ==14603== by 0x4F292E: display_sys_stats (kernel.c:5629) ==14603== by 0x464BC7: main_loop (main.c:797) ==14603== by 0x6BE352: captured_command_loop (main.c:258) ==14603== by 0x6BC959: catch_errors (exceptions.c:557) ==14603== by 0x6BF3D5: captured_main (main.c:1064) ==14603== by 0x6BC959: catch_errors (exceptions.c:557) ==14603== by 0x6BF686: gdb_main (main.c:1079) ==14603== by 0x6BF686: gdb_main_entry (main.c:1099) ==14603== by 0x46316F: main (main.c:708) ==14603== pages_to_size() removes ".0 " if it is contained in the created string by overwriting them using strcpy() with the following "MB\0" or "GB\0". However, strcpy() doesn't accept such overlapping source and destination and thus use of strcpy() in this case is illegal. Let's fix this by re-implementing the logic by memmove() where destination and source strings may overlap. Signed-off-by: HATAYAMA Daisuke <d.hatayama(a)fujitsu.com&gt;

--- tools.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/tools.c b/tools.c index 89352b1..71bac6d 100644 --- a/tools.c +++ b/tools.c @@ -6371,7 +6371,7 @@ char * pages_to_size(ulong pages, char *buf) { double total; - char *p1, *p2; + char *p; if (pages == 0) { sprintf(buf, "0"); @@ -6387,11 +6387,8 @@ pages_to_size(ulong pages, char *buf) else sprintf(buf, "%ld KB", (ulong)(total/(double)KILOBYTES(1))); - if ((p1 = strstr(buf, ".0 "))) { - p2 = p1 + 3; - *p1++ = ' '; - strcpy(p1, p2); - } + if ((p = strstr(buf, ".0 "))) + memmove(p, p + 2, sizeof(" GB")); return buf; } -- 2.29.2 -- Crash-utility mailing list Crash-utility(a)redhat.com https://www.redhat.com/mailman/listinfo/crash-utility