lkml.org 
[lkml]   [2019]   [Jan]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.19 067/106] perf svghelper: Fix unchecked usage of strncpy()
    Date
    4.19-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    [ Upstream commit 2f5302533f306d5ee87bd375aef9ca35b91762cb ]

    The strncpy() function may leave the destination string buffer
    unterminated, better use strlcpy() that we have a __weak fallback
    implementation for systems without it.

    In this specific case this would only happen if fgets() was buggy, as
    its man page states that it should read one less byte than the size of
    the destination buffer, so that it can put the nul byte at the end of
    it, so it would never copy 255 non-nul chars, as fgets reads into the
    orig buffer at most 254 non-nul chars and terminates it. But lets just
    switch to strlcpy to keep the original intent and silence the gcc 8.2
    warning.

    This fixes this warning on an Alpine Linux Edge system with gcc 8.2:

    In function 'cpu_model',
    inlined from 'svg_cpu_box' at util/svghelper.c:378:2:
    util/svghelper.c:337:5: error: 'strncpy' output may be truncated copying 255 bytes from a string of length 255 [-Werror=stringop-truncation]
    strncpy(cpu_m, &buf[13], 255);
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    Cc: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Jiri Olsa <jolsa@kernel.org>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Arjan van de Ven <arjan@linux.intel.com>
    Fixes: f48d55ce7871 ("perf: Add a SVG helper library file")
    Link: https://lkml.kernel.org/n/tip-xzkoo0gyr56gej39ltivuh9g@git.kernel.org
    Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    tools/perf/util/svghelper.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    diff --git a/tools/perf/util/svghelper.c b/tools/perf/util/svghelper.c
    index 1cbada2dc6be..f735ee038713 100644
    --- a/tools/perf/util/svghelper.c
    +++ b/tools/perf/util/svghelper.c
    @@ -334,7 +334,7 @@ static char *cpu_model(void)
    if (file) {
    while (fgets(buf, 255, file)) {
    if (strstr(buf, "model name")) {
    - strncpy(cpu_m, &buf[13], 255);
    + strlcpy(cpu_m, &buf[13], 255);
    break;
    }
    }
    --
    2.19.1


    \
     
     \ /
      Last update: 2019-01-24 20:53    [W:4.131 / U:0.020 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site