From: Tobias Stoeckmann Date: Sat, 16 Jul 2016 10:51:42 +0000 (+0200) Subject: tailf: Fix previously adjusted segfault patch X-Git-Tag: v2.29-rc1~149 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3f0e7f371a398a5b8ef23ff94651de13f4f987d3;p=thirdparty%2Futil-linux.git tailf: Fix previously adjusted segfault patch Casting the value to be checked to size_t renders the check useless. If st_size is SIZE_MAX+1, it will be truncated to 0 and the check succeeds. In fact, this check can never be false because every value stored in a size_t is smaller or equal to SIZE_MAX. I think this adjustment was meant to fix a compiler warning for 64 bit systems for which sizeof(off_t) is sizeof(size_t), but the signedness differs. Going unconditionally to the greatest possible unsigned int type if st_size is positive (off_t is signed) will fix this issue. Signed-off-by: Tobias Stoeckmann --- diff --git a/text-utils/tailf.c b/text-utils/tailf.c index 6219aa2189..34d0cd53b1 100644 --- a/text-utils/tailf.c +++ b/text-utils/tailf.c @@ -284,7 +284,7 @@ int main(int argc, char **argv) errx(EXIT_FAILURE, _("%s: is not a file"), filename); /* mmap is based on size_t */ - if (st.st_size && (size_t) st.st_size <= SIZE_MAX) + if (st.st_size > 0 && (uintmax_t) st.st_size <= (uintmax_t) SIZE_MAX) tailf(filename, lines, &st); #ifdef HAVE_INOTIFY_INIT