From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- fs/ecryptfs/debug.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 89 insertions(+) create mode 100644 fs/ecryptfs/debug.c (limited to 'fs/ecryptfs/debug.c') diff --git a/fs/ecryptfs/debug.c b/fs/ecryptfs/debug.c new file mode 100644 index 000000000..426437024 --- /dev/null +++ b/fs/ecryptfs/debug.c @@ -0,0 +1,89 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * eCryptfs: Linux filesystem encryption layer + * Functions only useful for debugging. + * + * Copyright (C) 2006 International Business Machines Corp. + * Author(s): Michael A. Halcrow + */ + +#include +#include "ecryptfs_kernel.h" + +/* + * ecryptfs_dump_auth_tok - debug function to print auth toks + * + * This function will print the contents of an ecryptfs authentication + * token. + */ +void ecryptfs_dump_auth_tok(struct ecryptfs_auth_tok *auth_tok) +{ + char salt[ECRYPTFS_SALT_SIZE * 2 + 1]; + char sig[ECRYPTFS_SIG_SIZE_HEX + 1]; + + ecryptfs_printk(KERN_DEBUG, "Auth tok at mem loc [%p]:\n", + auth_tok); + if (auth_tok->flags & ECRYPTFS_PRIVATE_KEY) { + ecryptfs_printk(KERN_DEBUG, " * private key type\n"); + } else { + ecryptfs_printk(KERN_DEBUG, " * passphrase type\n"); + ecryptfs_to_hex(salt, auth_tok->token.password.salt, + ECRYPTFS_SALT_SIZE); + ecryptfs_printk(KERN_DEBUG, " * salt = [%s]\n", salt); + if (auth_tok->token.password.flags & + ECRYPTFS_PERSISTENT_PASSWORD) { + ecryptfs_printk(KERN_DEBUG, " * persistent\n"); + } + strscpy(sig, auth_tok->token.password.signature); + ecryptfs_printk(KERN_DEBUG, " * signature = [%s]\n", sig); + } + ecryptfs_printk(KERN_DEBUG, " * session_key.flags = [0x%x]\n", + auth_tok->session_key.flags); + if (auth_tok->session_key.flags + & ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT) + ecryptfs_printk(KERN_DEBUG, + " * Userspace decrypt request set\n"); + if (auth_tok->session_key.flags + & ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT) + ecryptfs_printk(KERN_DEBUG, + " * Userspace encrypt request set\n"); + if (auth_tok->session_key.flags & ECRYPTFS_CONTAINS_DECRYPTED_KEY) { + ecryptfs_printk(KERN_DEBUG, " * Contains decrypted key\n"); + ecryptfs_printk(KERN_DEBUG, + " * session_key.decrypted_key_size = [0x%x]\n", + auth_tok->session_key.decrypted_key_size); + ecryptfs_printk(KERN_DEBUG, " * Decrypted session key " + "dump:\n"); + if (ecryptfs_verbosity > 0) + ecryptfs_dump_hex(auth_tok->session_key.decrypted_key, + ECRYPTFS_DEFAULT_KEY_BYTES); + } + if (auth_tok->session_key.flags & ECRYPTFS_CONTAINS_ENCRYPTED_KEY) { + ecryptfs_printk(KERN_DEBUG, " * Contains encrypted key\n"); + ecryptfs_printk(KERN_DEBUG, + " * session_key.encrypted_key_size = [0x%x]\n", + auth_tok->session_key.encrypted_key_size); + ecryptfs_printk(KERN_DEBUG, " * Encrypted session key " + "dump:\n"); + if (ecryptfs_verbosity > 0) + ecryptfs_dump_hex(auth_tok->session_key.encrypted_key, + auth_tok->session_key. + encrypted_key_size); + } +} + +/** + * ecryptfs_dump_hex - debug hex printer + * @data: string of bytes to be printed + * @bytes: number of bytes to print + * + * Dump hexadecimal representation of char array + */ +void ecryptfs_dump_hex(char *data, int bytes) +{ + if (ecryptfs_verbosity < 1) + return; + + print_hex_dump(KERN_DEBUG, "ecryptfs: ", DUMP_PREFIX_OFFSET, 16, 1, + data, bytes, false); +} -- cgit v1.3.1