Commit 82bc1ef4 authored by Jingbo Xu's avatar Jingbo Xu Committed by Gao Xiang
Browse files

erofs: handle long xattr name prefixes properly 



Make .{list,get}xattr routines adapted to long xattr name prefixes.
When the bit 7 of erofs_xattr_entry.e_name_index is set, it indicates
that it refers to a long xattr name prefix.

Signed-off-by: default avatarJingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
Acked-by: default avatarChao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20230411093537.127286-1-jefflexu@linux.alibaba.com


Signed-off-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
parent 9e382914

fs/erofs/xattr.c

+56 −12
Original line number Diff line number Diff line
@@ -297,17 +297,45 @@ struct getxattr_iter { 
	struct xattr_iter it;



	char *buffer;

	int buffer_size, index;

	int buffer_size, index, infix_len;

	struct qstr name;

};



static int erofs_xattr_long_entrymatch(struct getxattr_iter *it,

				       struct erofs_xattr_entry *entry)

{

	struct erofs_sb_info *sbi = EROFS_SB(it->it.sb);

	struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes +

		(entry->e_name_index & EROFS_XATTR_LONG_PREFIX_MASK);



	if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count)

		return -ENOATTR;



	if (it->index != pf->prefix->base_index ||

	    it->name.len != entry->e_name_len + pf->infix_len)

		return -ENOATTR;



	if (memcmp(it->name.name, pf->prefix->infix, pf->infix_len))

		return -ENOATTR;



	it->infix_len = pf->infix_len;

	return 0;

}



static int xattr_entrymatch(struct xattr_iter *_it,

			    struct erofs_xattr_entry *entry)

{

	struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);



	return (it->index != entry->e_name_index ||

		it->name.len != entry->e_name_len) ? -ENOATTR : 0;

	/* should also match the infix for long name prefixes */

	if (entry->e_name_index & EROFS_XATTR_LONG_PREFIX)

		return erofs_xattr_long_entrymatch(it, entry);



	if (it->index != entry->e_name_index ||

	    it->name.len != entry->e_name_len)

		return -ENOATTR;

	it->infix_len = 0;

	return 0;

}



static int xattr_namematch(struct xattr_iter *_it,
@@ -315,7 +343,9 @@ static int xattr_namematch(struct xattr_iter *_it, 
{

	struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);



	return memcmp(buf, it->name.name + processed, len) ? -ENOATTR : 0;

	if (memcmp(buf, it->name.name + it->infix_len + processed, len))

		return -ENOATTR;

	return 0;

}



static int xattr_checkbuffer(struct xattr_iter *_it,
@@ -487,12 +517,24 @@ static int xattr_entrylist(struct xattr_iter *_it, 
{

	struct listxattr_iter *it =

		container_of(_it, struct listxattr_iter, it);

	unsigned int prefix_len;

	const char *prefix;

	unsigned int base_index = entry->e_name_index;

	unsigned int prefix_len, infix_len = 0;

	const char *prefix, *infix = NULL;

	const struct xattr_handler *h;



	if (entry->e_name_index & EROFS_XATTR_LONG_PREFIX) {

		struct erofs_sb_info *sbi = EROFS_SB(_it->sb);

		struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes +

			(entry->e_name_index & EROFS_XATTR_LONG_PREFIX_MASK);



	const struct xattr_handler *h =

		erofs_xattr_handler(entry->e_name_index);

		if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count)

			return 1;

		infix = pf->prefix->infix;

		infix_len = pf->infix_len;

		base_index = pf->prefix->base_index;

	}



	h = erofs_xattr_handler(base_index);

	if (!h || (h->list && !h->list(it->dentry)))

		return 1;
@@ -500,16 +542,18 @@ static int xattr_entrylist(struct xattr_iter *_it, 
	prefix_len = strlen(prefix);



	if (!it->buffer) {

		it->buffer_ofs += prefix_len + entry->e_name_len + 1;

		it->buffer_ofs += prefix_len + infix_len +

					entry->e_name_len + 1;

		return 1;

	}



	if (it->buffer_ofs + prefix_len

	if (it->buffer_ofs + prefix_len + infix_len +

		+ entry->e_name_len + 1 > it->buffer_size)

		return -ERANGE;



	memcpy(it->buffer + it->buffer_ofs, prefix, prefix_len);

	it->buffer_ofs += prefix_len;

	memcpy(it->buffer + it->buffer_ofs + prefix_len, infix, infix_len);

	it->buffer_ofs += prefix_len + infix_len;

	return 0;

}