From 91cda136ef27402256dbf85434374b43ab52d932 Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Fri, 11 Aug 2017 11:15:30 +0200 Subject: [PATCH] bpf: Make bytecode-file reading a little more robust Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1477491 Upstream Status: iproute2.git commit 3da3ebfca85b8 commit 3da3ebfca85b8f1e8252b898453d8cb383c5c398 Author: Phil Sutter Date: Wed Aug 2 14:57:56 2017 +0200 bpf: Make bytecode-file reading a little more robust bpf_parse_string() will now correctly handle: - Extraneous whitespace, - OPs on multiple lines and - overlong file names. The added feature of allowing to have OPs on multiple lines (like e.g. tcpdump prints them) is rather a side effect of fixing detection of malformed bytecode files having random content on a second line, like e.g.: | 4,40 0 0 12,21 0 1 2048,6 0 0 262144,6 0 0 0 | foobar Cc: Daniel Borkmann Signed-off-by: Phil Sutter Acked-by: Daniel Borkmann --- lib/bpf.c | 32 ++++++++++++++++++++++++-------- 1 file changed, 24 insertions(+), 8 deletions(-) diff --git a/lib/bpf.c b/lib/bpf.c index 04ee1ab..73dac5c 100644 --- a/lib/bpf.c +++ b/lib/bpf.c @@ -160,11 +160,11 @@ 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, *last; + char *tmp_string, *pos, c, c_prev = ' '; FILE *fp; tmp_len = sizeof("4096,") + BPF_MAXINSNS * op_len; - tmp_string = calloc(1, tmp_len); + tmp_string = pos = calloc(1, tmp_len); if (tmp_string == NULL) return -ENOMEM; @@ -175,17 +175,33 @@ static int bpf_parse_string(char *arg, bool from_file, __u16 *bpf_len, return -ENOENT; } - if (!fgets(tmp_string, tmp_len, fp)) { + while ((c = fgetc(fp)) != EOF) { + switch (c) { + case '\n': + if (c_prev != ',') + *(pos++) = ','; + break; + case ' ': + case '\t': + if (c_prev != ' ') + *(pos++) = c; + break; + default: + *(pos++) = c; + } + if (pos - tmp_string == tmp_len) + break; + c_prev = c; + } + + if (!feof(fp)) { free(tmp_string); fclose(fp); - return -EIO; + return -E2BIG; } fclose(fp); - - last = &tmp_string[strlen(tmp_string) - 1]; - if (*last == '\n') - *last = 0; + *pos = 0; *need_release = true; *bpf_string = tmp_string; -- 1.8.3.1