Patch "f2fs crypto: allocate buffer for decrypting filename" has been added to the 4.3-stable tree

This is a note to let you know that I've just added the patch titled

f2fs crypto: allocate buffer for decrypting filename

to the 4.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
f2fs-crypto-allocate-buffer-for-decrypting-filename.patch
and it can be found in the queue-4.3 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Jaegeuk Kim <[email protected]>
Date: Thu, 3 Sep 2015 13:38:23 -0700
Subject: f2fs crypto: allocate buffer for decrypting filename

From: Jaegeuk Kim <[email protected]>

commit 569cf1876a32e574ba8a7fb825cd91bafd003882 upstream.

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)

---
 fs/f2fs/dir.c   |   13 ++++++++++---
 fs/f2fs/namei.c |   10 +++++++++-
 2 files changed, 19 insertions(+), 4 deletions(-)

@@ -787,7 +787,6 @@ bool f2fs_fill_dentries(struct dir_conte
 		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_conte
 			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,

@@ -947,8 +947,13 @@ static const char *f2fs_encrypted_follow
 
 	/* 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
 	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
 	page_cache_release(cpage);
 	return *cookie = paddr;
 errout:
+	kfree(cstr.name);
 	f2fs_fname_crypto_free_buffer(&pstr);
 	kunmap(cpage);
 	page_cache_release(cpage);

Patches currently in stable-queue which might be from [email protected] are

queue-4.3/f2fs-crypto-allocate-buffer-for-decrypting-filename.patch