Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.5 207/399] tools lib api fs: Fix gcc9 stringop-truncation compilation error | Date | Fri, 21 Feb 2020 08:38:52 +0100 |
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From: Andrey Zhizhikin <andrey.z@gmail.com>
[ Upstream commit 6794200fa3c9c3e6759dae099145f23e4310f4f7 ]
GCC9 introduced string hardening mechanisms, which exhibits the error during fs api compilation:
error: '__builtin_strncpy' specified bound 4096 equals destination size [-Werror=stringop-truncation]
This comes when the length of copy passed to strncpy is is equal to destination size, which could potentially lead to buffer overflow.
There is a need to mitigate this potential issue by limiting the size of destination by 1 and explicitly terminate the destination with NULL.
Signed-off-by: Andrey Zhizhikin <andrey.zhizhikin@leica-geosystems.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andriin@fb.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Martin KaFai Lau <kafai@fb.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Song Liu <songliubraving@fb.com> Cc: Yonghong Song <yhs@fb.com> Cc: bpf@vger.kernel.org Cc: netdev@vger.kernel.org Link: http://lore.kernel.org/lkml/20191211080109.18765-1-andrey.zhizhikin@leica-geosystems.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> --- tools/lib/api/fs/fs.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/tools/lib/api/fs/fs.c b/tools/lib/api/fs/fs.c index 11b3885e833ed..027b18f7ed8cf 100644 --- a/tools/lib/api/fs/fs.c +++ b/tools/lib/api/fs/fs.c @@ -210,6 +210,7 @@ static bool fs__env_override(struct fs *fs) size_t name_len = strlen(fs->name); /* name + "_PATH" + '\0' */ char upper_name[name_len + 5 + 1]; + memcpy(upper_name, fs->name, name_len); mem_toupper(upper_name, name_len); strcpy(&upper_name[name_len], "_PATH"); @@ -219,7 +220,8 @@ static bool fs__env_override(struct fs *fs) return false; fs->found = true; - strncpy(fs->path, override_path, sizeof(fs->path)); + strncpy(fs->path, override_path, sizeof(fs->path) - 1); + fs->path[sizeof(fs->path) - 1] = '\0'; return true; } -- 2.20.1
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