patch 9.1.0162: problem with writing extended attributes on failure
Problem: problem with writing extended attributes on failure
Solution: Change return type to ssize_t and check listxattr's return
value correctly on failure (Paul Tagliamonte)
The existing logic will return when the listxattr call returns with the
errno set to ENOTSUP (or a size of 0 bytes), without checking to see if
listxattr actually failed. listxattr can fail with at least E2BIG,
ENOTSUP, ERANGE, or anything that `stat(2)` can fail with (in my case;
ENOENT from stat).
The returned size is stored to a size_t, but the return type is a
ssize_t. On failure, listxattr returns -1, which will get translated to
size_t's MAX. If the listxattr call failed with anything other than
ENOTSUP, this triggers a request for size_t MAX bytes.
This means that, if the listxattr call fails with anything other than
ENOTSUP on save, vim will error with
`E342: Out of memory! (allocating 18446744073709551615 bytes)`
(keen observers will note 18446744073709551615 is 0xffffffffffffffff)
In reality, this is likely masking a different (usually filesystem?)
error -- but at least it's an error being pushed to the user now, and we
don't try to allocate size_t MAX bytes.
I've opted to change the type that we store listxattr to from size_t to
ssize_t, to match listxattr(2)'s signature, and to check for the -1
return value. Additionally, I've removed the errno check -- if we get a
listxattr failure for any reason, we may as well bail without trying;
it's not like we can even recover.
closes: #14169
Signed-off-by: Paul Tagliamonte <paultag@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/os_unix.c b/src/os_unix.c
index dae5bbe..e98911e 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -3048,7 +3048,7 @@
size = listxattr((char *)from_file, NULL, 0);
// not supported or no attributes to copy
- if (errno == ENOTSUP || size == 0)
+ if (size <= 0)
return;
for (index = 0 ; index < (int)(sizeof(smack_copied_attributes)
@@ -3112,8 +3112,8 @@
mch_copy_xattr(char_u *from_file, char_u *to_file)
{
char *xattr_buf;
- size_t size;
- size_t tsize;
+ ssize_t size;
+ ssize_t tsize;
ssize_t keylen, vallen, max_vallen = 0;
char *key;
char *val = NULL;
@@ -3125,7 +3125,7 @@
// get the length of the extended attributes
size = listxattr((char *)from_file, NULL, 0);
// not supported or no attributes to copy
- if (errno == ENOTSUP || size == 0)
+ if (size <= 0)
return;
xattr_buf = (char*)alloc(size);
if (xattr_buf == NULL)