[Virtio-fs] [PATCH v6 3/8] virtiofsd: Fix xattr operations overwriting errno
Vivek Goyal
vgoyal at redhat.com
Thu Jun 17 18:12:08 UTC 2021
getxattr/setxattr/removexattr/listxattr operations handle regualar
and non-regular files differently. For the case of non-regular files
we do fchdir(/proc/self/fd) and the xattr operation and then revert
back to original working directory. After this we are saving errno
and that's buggy because fchdir() will overwrite the errno.
FCHDIR_NOFAIL(lo->proc_self_fd);
ret = getxattr(procname, name, value, size);
FCHDIR_NOFAIL(lo->root.fd);
if (ret == -1)
saverr = errno
In above example, if getxattr() failed, we will still return 0 to caller
as errno must have been written by FCHDIR_NOFAIL(lo->root.fd) call.
Fix all such instances and capture "errno" early and save in "saverr"
variable.
Signed-off-by: Vivek Goyal <vgoyal at redhat.com>
---
tools/virtiofsd/passthrough_ll.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
index 49c21fd855..ec91b3c133 100644
--- a/tools/virtiofsd/passthrough_ll.c
+++ b/tools/virtiofsd/passthrough_ll.c
@@ -2791,15 +2791,17 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name,
goto out_err;
}
ret = fgetxattr(fd, name, value, size);
+ saverr = ret == -1 ? errno : 0;
} else {
/* fchdir should not fail here */
FCHDIR_NOFAIL(lo->proc_self_fd);
ret = getxattr(procname, name, value, size);
+ saverr = ret == -1 ? errno : 0;
FCHDIR_NOFAIL(lo->root.fd);
}
if (ret == -1) {
- goto out_err;
+ goto out;
}
if (size) {
saverr = 0;
@@ -2864,15 +2866,17 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size)
goto out_err;
}
ret = flistxattr(fd, value, size);
+ saverr = ret == -1 ? errno : 0;
} else {
/* fchdir should not fail here */
FCHDIR_NOFAIL(lo->proc_self_fd);
ret = listxattr(procname, value, size);
+ saverr = ret == -1 ? errno : 0;
FCHDIR_NOFAIL(lo->root.fd);
}
if (ret == -1) {
- goto out_err;
+ goto out;
}
if (size) {
saverr = 0;
@@ -2998,15 +3002,15 @@ static void lo_setxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name,
goto out;
}
ret = fsetxattr(fd, name, value, size, flags);
+ saverr = ret == -1 ? errno : 0;
} else {
/* fchdir should not fail here */
FCHDIR_NOFAIL(lo->proc_self_fd);
ret = setxattr(procname, name, value, size, flags);
+ saverr = ret == -1 ? errno : 0;
FCHDIR_NOFAIL(lo->root.fd);
}
- saverr = ret == -1 ? errno : 0;
-
out:
if (fd >= 0) {
close(fd);
@@ -3064,15 +3068,15 @@ static void lo_removexattr(fuse_req_t req, fuse_ino_t ino, const char *in_name)
goto out;
}
ret = fremovexattr(fd, name);
+ saverr = ret == -1 ? errno : 0;
} else {
/* fchdir should not fail here */
FCHDIR_NOFAIL(lo->proc_self_fd);
ret = removexattr(procname, name);
+ saverr = ret == -1 ? errno : 0;
FCHDIR_NOFAIL(lo->root.fd);
}
- saverr = ret == -1 ? errno : 0;
-
out:
if (fd >= 0) {
close(fd);
--
2.25.4
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