diff options
author | Rich Felker <dalias@aerifal.cx> | 2020-09-09 21:55:11 -0400 |
---|---|---|
committer | Rich Felker <dalias@aerifal.cx> | 2020-09-09 21:55:11 -0400 |
commit | 55fb9a177316aa46c639d93dd0323d9a9a8c160c (patch) | |
tree | e48ec6bc0079a981fe17ba9314b28378055a01c4 /src/unistd/faccessat.c | |
parent | f035c7b1e65b6566c979ed69bada82a466580ba2 (diff) | |
download | musl-55fb9a177316aa46c639d93dd0323d9a9a8c160c.tar.gz musl-55fb9a177316aa46c639d93dd0323d9a9a8c160c.tar.bz2 musl-55fb9a177316aa46c639d93dd0323d9a9a8c160c.tar.xz musl-55fb9a177316aa46c639d93dd0323d9a9a8c160c.zip |
use new SYS_faccessat2 syscall to implement faccessat with flags
commit 0a05eace163cee9b08571d2ff9d90f5e82d9c228 implemented AT_EACCESS
for faccessat with a horrible hack, creating a child process to change
switch uid/gid and perform the access probe without making potentially
irreversible changes to the caller's credentials. this was due to the
syscall lacking a flags argument.
linux 5.8 introduced a new syscall, SYS_faccessat2, fixing this
deficiency. use it if any flags are passed, and fallback to the old
strategy on ENOSYS. continue using the old syscall when there are no
flags.
Diffstat (limited to 'src/unistd/faccessat.c')
-rw-r--r-- | src/unistd/faccessat.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/src/unistd/faccessat.c b/src/unistd/faccessat.c index 76bbd4c7..557503eb 100644 --- a/src/unistd/faccessat.c +++ b/src/unistd/faccessat.c @@ -25,12 +25,17 @@ static int checker(void *p) int faccessat(int fd, const char *filename, int amode, int flag) { - if (!flag || (flag==AT_EACCESS && getuid()==geteuid() && getgid()==getegid())) - return syscall(SYS_faccessat, fd, filename, amode, flag); + if (flag) { + int ret = __syscall(SYS_faccessat2, fd, filename, amode, flag); + if (ret != -ENOSYS) return __syscall_ret(ret); + } - if (flag != AT_EACCESS) + if (flag & ~AT_EACCESS) return __syscall_ret(-EINVAL); + if (!flag || (getuid()==geteuid() && getgid()==getegid())) + return syscall(SYS_faccessat, fd, filename, amode); + char stack[1024]; sigset_t set; pid_t pid; |