From 584ca9f67952162dfdd02d984aa12640e45a4235 Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Wed, 6 Sep 2017 11:53:53 +0200 Subject: [PATCH] lib/bpf: Fix bytecode-file parsing Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1477491 Upstream Status: iproute2.git commit 7c87c7fed18d1 commit 7c87c7fed18d1162e045c8331cb68fa440bc5728 Author: Phil Sutter Date: Tue Aug 29 17:09:45 2017 +0200 lib/bpf: Fix bytecode-file parsing The signedness of char type is implementation dependent, and there are architectures on which it is unsigned by default. In that case, the check whether fgetc() returned EOF failed because the return value was assigned an (unsigned) char variable prior to comparison with EOF (which is defined to -1). Fix this by using int as type for 'c' variable, which also matches the declaration of fgetc(). While being at it, fix the parser logic to correctly handle multiple empty lines and consecutive whitespace and tab characters to further improve the parser's robustness. Note that this will still detect double separator characters, so doesn't soften up the parser too much. Fixes: 3da3ebfca85b8 ("bpf: Make bytecode-file reading a little more robust") Cc: Daniel Borkmann Signed-off-by: Phil Sutter Acked-by: Daniel Borkmann --- lib/bpf.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/lib/bpf.c b/lib/bpf.c index 73dac5c37cc91..3aabf44d1abf8 100644 --- a/lib/bpf.c +++ b/lib/bpf.c @@ -160,8 +160,9 @@ static int bpf_parse_string(char *arg, bool from_file, __u16 *bpf_len, if (from_file) { size_t tmp_len, op_len = sizeof("65535 255 255 4294967295,"); - char *tmp_string, *pos, c, c_prev = ' '; + char *tmp_string, *pos, c_prev = ' '; FILE *fp; + int c; tmp_len = sizeof("4096,") + BPF_MAXINSNS * op_len; tmp_string = pos = calloc(1, tmp_len); @@ -180,18 +181,20 @@ static int bpf_parse_string(char *arg, bool from_file, __u16 *bpf_len, case '\n': if (c_prev != ',') *(pos++) = ','; + c_prev = ','; break; case ' ': case '\t': if (c_prev != ' ') *(pos++) = c; + c_prev = ' '; break; default: *(pos++) = c; + c_prev = c; } if (pos - tmp_string == tmp_len) break; - c_prev = c; } if (!feof(fp)) { -- 2.21.0