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Commit 569cf187 authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs crypto: allocate buffer for decrypting filename 



We got dentry pages from high_mem, and its address space directly goes into the
decryption path via f2fs_fname_disk_to_usr.
But, sg_init_one assumes the address is not from high_mem, so we can get this
panic since it doesn't call kmap_high but kunmap_high is triggered at the end.

kernel BUG at ../../../../../../kernel/mm/highmem.c:290!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
...
 (kunmap_high+0xb0/0xb8) from [<c0114534>] (__kunmap_atomic+0xa0/0xa4)
 (__kunmap_atomic+0xa0/0xa4) from [<c035f028>] (blkcipher_walk_done+0x128/0x1ec)
 (blkcipher_walk_done+0x128/0x1ec) from [<c0366c24>] (crypto_cbc_decrypt+0xc0/0x170)
 (crypto_cbc_decrypt+0xc0/0x170) from [<c0367148>] (crypto_cts_decrypt+0xc0/0x114)
 (crypto_cts_decrypt+0xc0/0x114) from [<c035ea98>] (async_decrypt+0x40/0x48)
 (async_decrypt+0x40/0x48) from [<c032ca34>] (f2fs_fname_disk_to_usr+0x124/0x304)
 (f2fs_fname_disk_to_usr+0x124/0x304) from [<c03056fc>] (f2fs_fill_dentries+0xac/0x188)
 (f2fs_fill_dentries+0xac/0x188) from [<c03059c8>] (f2fs_readdir+0x1f0/0x300)
 (f2fs_readdir+0x1f0/0x300) from [<c0218054>] (vfs_readdir+0x90/0xb4)
 (vfs_readdir+0x90/0xb4) from [<c0218418>] (SyS_getdents64+0x64/0xcc)
 (SyS_getdents64+0x64/0xcc) from [<c0105ba0>] (ret_fast_syscall+0x0/0x30)

Cc: <stable@vger.kernel.org>
Reviewed-by: default avatarChao Yu <chao2.yu@samsung.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 973163fc

fs/f2fs/dir.c

+10 −3
Original line number Diff line number Diff line
@@ -787,7 +787,6 @@ bool f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d, 
		else

			d_type = DT_UNKNOWN;



		/* encrypted case */

		de_name.name = d->filename[bit_pos];

		de_name.len = le16_to_cpu(de->name_len);
@@ -795,12 +794,20 @@ bool f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d, 
			int save_len = fstr->len;

			int ret;



			de_name.name = kmalloc(de_name.len, GFP_NOFS);

			if (!de_name.name)

				return false;



			memcpy(de_name.name, d->filename[bit_pos], de_name.len);



			ret = f2fs_fname_disk_to_usr(d->inode, &de->hash_code,

							&de_name, fstr);

			de_name = *fstr;

			fstr->len = save_len;

			kfree(de_name.name);

			if (ret < 0)

				return true;



			de_name = *fstr;

			fstr->len = save_len;

		}



		if (!dir_emit(ctx, de_name.name, de_name.len,

fs/f2fs/namei.c

+9 −1
Original line number Diff line number Diff line
@@ -947,8 +947,13 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook 


	/* Symlink is encrypted */

	sd = (struct f2fs_encrypted_symlink_data *)caddr;

	cstr.name = sd->encrypted_path;

	cstr.len = le16_to_cpu(sd->len);

	cstr.name = kmalloc(cstr.len, GFP_NOFS);

	if (!cstr.name) {

		res = -ENOMEM;

		goto errout;

	}

	memcpy(cstr.name, sd->encrypted_path, cstr.len);



	/* this is broken symlink case */

	if (cstr.name[0] == 0 && cstr.len == 0) {
@@ -970,6 +975,8 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook 
	if (res < 0)

		goto errout;



	kfree(cstr.name);



	paddr = pstr.name;



	/* Null-terminate the name */
@@ -979,6 +986,7 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook 
	page_cache_release(cpage);

	return *cookie = paddr;

errout:

	kfree(cstr.name);

	f2fs_fname_crypto_free_buffer(&pstr);

	kunmap(cpage);

	page_cache_release(cpage);