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| author | Karel Zak <kzak@redhat.com> | 2021-06-17 13:28:32 +0200 |
|---|---|---|
| committer | Karel Zak <kzak@redhat.com> | 2021-06-17 13:28:32 +0200 |
| commit | 9dbae34c3da7667319df2191b4b0fee6552dd0e3 (patch) | |
| tree | 84008792720ae4e5e6439de525998c2a34f8cd4e /lib/path.c | |
| parent | 2384fa6e4d086656ea7ae890d2ac2bdce08ca0e6 (diff) | |
| download | util-linux-9dbae34c3da7667319df2191b4b0fee6552dd0e3.tar.gz | |
lib/path: improve ul_path_readlink() to be more robust
According to POSIX, readlink() makes no effort to null-terminate buffer
with the result. It seems better to hide this disadvantage in the
ul_path_...() API rather than assume buf[sz] = '\0' everywhere.
Reported-by: Reported-by: Jan Pazdziora <jpazdziora@redhat.com>
Signed-off-by: Karel Zak <kzak@redhat.com>
Diffstat (limited to 'lib/path.c')
| -rw-r--r-- | lib/path.c | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/lib/path.c b/lib/path.c index 058c143f40..7576328d7c 100644 --- a/lib/path.c +++ b/lib/path.c @@ -542,22 +542,27 @@ DIR *ul_path_opendirf(struct path_cxt *pc, const char *path, ...) ssize_t ul_path_readlink(struct path_cxt *pc, char *buf, size_t bufsiz, const char *path) { int dirfd; + ssize_t ssz; if (!path) { const char *p = get_absdir(pc); if (!p) return -errno; - return readlink(p, buf, bufsiz); - } + ssz = readlink(p, buf, bufsiz - 1); + } else { + dirfd = ul_path_get_dirfd(pc); + if (dirfd < 0) + return dirfd; - dirfd = ul_path_get_dirfd(pc); - if (dirfd < 0) - return dirfd; + if (*path == '/') + path++; - if (*path == '/') - path++; + ssz = readlinkat(dirfd, path, buf, bufsiz - 1); + } - return readlinkat(dirfd, path, buf, bufsiz); + if (ssz >= 0) + buf[ssz] = '\0'; + return ssz; } /* |