tools lib api fs: Fix gcc9 stringop-truncation compilation error

[ 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 <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Andrii Nakryiko <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: Kefeng Wang <[email protected]>
Cc: Martin KaFai Lau <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: Song Liu <[email protected]>
Cc: Yonghong Song <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
This commit is contained in:
Andrey Zhizhikin 2019-12-11 08:01:09 +00:00 • committed by Greg Kroah-Hartman
commit e44b48f5bb

View file

@ -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;
}