mirror/flatpak
1
0
Fork 0
mirror of https://github.com/flatpak/flatpak.git synced 2026-03-28 03:45:10 -04:00
Code Issues Packages Projects Releases Wiki Activity

listxattr: Don't assume that first call to listxattr gives correct size

Browse Source 
To get the right sized buffer to pass to `flistattr` and `llistattr` we
first call them with a zero byte buffer.  They then return the number of
bytes they'll actually need to operate.  We would `malloc` and then call
again assuming that the size we got originally was correct.

On my computer at least this isn't always the case.  I've seen instances
where the first call returns 23B, but then on the second one returns no
data at all.  Getting these non-existant xattrs would then cause ostree
to fail.

I'm not sure why it's behaving this way on my machine.  I suspect its some
interaction with overlayfs but I haven't proven this.
This commit is contained in:
William Manley
2017-01-10 15:13:56 +00:00
committed by Colin Walters
parent 597f03b405
commit 6bf55255e8
1 changed files with 20 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

32
glnx-xattrs.c
View File

@@ -135,7 +135,7 @@ get_xattrs_impl (const char *path,
GError **error)
{
gboolean ret = FALSE;
ssize_t bytes_read;
ssize_t bytes_read, real_size;
glnx_free char *xattr_names = NULL;
glnx_free char *xattr_names_canonical = NULL;
GVariantBuilder builder;
@@ -158,15 +158,19 @@ get_xattrs_impl (const char *path,
else if (bytes_read > 0)
{
xattr_names = g_malloc (bytes_read);
if (llistxattr (path, xattr_names, bytes_read) < 0)
real_size = llistxattr (path, xattr_names, bytes_read);
if (real_size < 0)
{
glnx_set_prefix_error_from_errno (error, "%s", "llistxattr");
goto out;
}
xattr_names_canonical = canonicalize_xattrs (xattr_names, bytes_read);
if (!read_xattr_name_array (path, -1, xattr_names_canonical, bytes_read, &builder, error))
goto out;
else if (real_size > 0)
{
xattr_names_canonical = canonicalize_xattrs (xattr_names, real_size);
if (!read_xattr_name_array (path, -1, xattr_names_canonical, real_size, &builder, error))
goto out;
}
}
ret_xattrs = g_variant_builder_end (&builder);
@@ -202,7 +206,7 @@ glnx_fd_get_all_xattrs (int fd,
GError **error)
{
gboolean ret = FALSE;
ssize_t bytes_read;
ssize_t bytes_read, real_size;
glnx_free char *xattr_names = NULL;
glnx_free char *xattr_names_canonical = NULL;
GVariantBuilder builder;
@@ -225,15 +229,19 @@ glnx_fd_get_all_xattrs (int fd,
else if (bytes_read > 0)
{
xattr_names = g_malloc (bytes_read);
if (flistxattr (fd, xattr_names, bytes_read) < 0)
real_size = flistxattr (fd, xattr_names, bytes_read);
if (real_size < 0)
{
glnx_set_prefix_error_from_errno (error, "%s", "flistxattr");
goto out;
}
xattr_names_canonical = canonicalize_xattrs (xattr_names, bytes_read);
if (!read_xattr_name_array (NULL, fd, xattr_names_canonical, bytes_read, &builder, error))
goto out;
else if (real_size > 0)
{
xattr_names_canonical = canonicalize_xattrs (xattr_names, real_size);
if (!read_xattr_name_array (NULL, fd, xattr_names_canonical, real_size, &builder, error))
goto out;
}
}
ret_xattrs = g_variant_builder_end (&builder);