oss-fuzz: always turn off logging on OSS-Fuzz

Apparently /proc/self/cmd can't be used (reliably) on OSS-Fuzz to figure out
whether the code is run inside the fuzz targets, which causes the
fuzz targets to fill the filesystem with log files.

Related: https://github.com/google/oss-fuzz/issues/5509
Should address https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=33835

Signed-off-by: Evgeny Vereshchagin <evvers@ya.ru>

diff --git a/configure.ac b/configure.ac
index 1fe05a63aceec77f7cc7cca9e9cd10b581e65dfa..00cdaf0812ede816561ade5eae3e2a91625cfe4b 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -488,7 +488,11 @@ if test "x$enable_fuzzers" = "xyes"; then
        if test "x$LIB_FUZZING_ENGINE" = x; then
                CC_CHECK_FLAGS_APPEND([AM_CFLAGS],[CFLAGS],[ \
                        -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION \
+                       -DRUN_ON_OSS_FUZZ=0 \
                        -fsanitize=fuzzer-no-link])
+       else
+               CC_CHECK_FLAGS_APPEND([AM_CFLAGS],[CFLAGS],[ \
+                       -DRUN_ON_OSS_FUZZ=1])
        fi
 else
        CC_CHECK_FLAGS_APPEND([AM_CFLAGS],[CFLAGS],[-flto=thin])

diff --git a/src/lxc/log.c b/src/lxc/log.c
index 844c1cefb73910cd0b58f3eeabe1020e7f712f0d..be3a16fcc1a0ebc5b23a205e703a358e9b05761c 100644 (file)
--- a/src/lxc/log.c
+++ b/src/lxc/log.c
@@ -508,7 +508,7 @@ static int build_dir(const char *name)
 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
                ret = lxc_unpriv(mkdir(n, 0755));
 #else
-               if (is_in_comm("fuzz-lxc-") > 0)
+               if (RUN_ON_OSS_FUZZ || is_in_comm("fuzz-lxc-") > 0)
                        ret = errno = EEXIST;
                else
                        ret = lxc_unpriv(mkdir(n, 0755));
@@ -529,7 +529,7 @@ static int log_open(const char *name)
 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
        fd = lxc_unpriv(open(name, O_CREAT | O_WRONLY | O_APPEND | O_CLOEXEC, 0660));
 #else
-       if (is_in_comm("fuzz-lxc-") <= 0)
+       if (!RUN_ON_OSS_FUZZ && is_in_comm("fuzz-lxc-") <= 0)
                fd = lxc_unpriv(open(name, O_CREAT | O_WRONLY | O_APPEND | O_CLOEXEC, 0660));
 #endif /* !FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION */
        if (fd < 0)