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 --- crypto/proc.c | 103 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 103 insertions(+) create mode 100644 crypto/proc.c (limited to 'crypto/proc.c') diff --git a/crypto/proc.c b/crypto/proc.c new file mode 100644 index 000000000..5fb9fe86d --- /dev/null +++ b/crypto/proc.c @@ -0,0 +1,103 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Scatterlist Cryptographic API. + * + * Procfs information. + * + * Copyright (c) 2002 James Morris + * Copyright (c) 2005 Herbert Xu + */ + +#include +#include +#include +#include +#include /* for module_name() */ +#include +#include +#include +#include "internal.h" + +static void *c_start(struct seq_file *m, loff_t *pos) + __acquires_shared(&crypto_alg_sem) +{ + down_read(&crypto_alg_sem); + return seq_list_start(&crypto_alg_list, *pos); +} + +static void *c_next(struct seq_file *m, void *p, loff_t *pos) + __must_hold_shared(&crypto_alg_sem) +{ + return seq_list_next(p, &crypto_alg_list, pos); +} + +static void c_stop(struct seq_file *m, void *p) + __releases_shared(&crypto_alg_sem) +{ + up_read(&crypto_alg_sem); +} + +static int c_show(struct seq_file *m, void *p) +{ + struct crypto_alg *alg = list_entry(p, struct crypto_alg, cra_list); + + seq_printf(m, "name : %s\n", alg->cra_name); + seq_printf(m, "driver : %s\n", alg->cra_driver_name); + seq_printf(m, "module : %s\n", module_name(alg->cra_module)); + seq_printf(m, "priority : %d\n", alg->cra_priority); + seq_printf(m, "refcnt : %u\n", refcount_read(&alg->cra_refcnt)); + seq_printf(m, "selftest : %s\n", + (alg->cra_flags & CRYPTO_ALG_TESTED) ? + "passed" : "unknown"); + seq_printf(m, "internal : %s\n", + str_yes_no(alg->cra_flags & CRYPTO_ALG_INTERNAL)); + if (fips_enabled) + seq_printf(m, "fips : %s\n", + str_no_yes(alg->cra_flags & CRYPTO_ALG_FIPS_INTERNAL)); + + if (alg->cra_flags & CRYPTO_ALG_LARVAL) { + seq_printf(m, "type : larval\n"); + seq_printf(m, "flags : 0x%x\n", alg->cra_flags); + goto out; + } + + if (alg->cra_type && alg->cra_type->show) { + alg->cra_type->show(m, alg); + goto out; + } + + switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) { + case CRYPTO_ALG_TYPE_CIPHER: + seq_printf(m, "type : cipher\n"); + seq_printf(m, "blocksize : %u\n", alg->cra_blocksize); + seq_printf(m, "min keysize : %u\n", + alg->cra_cipher.cia_min_keysize); + seq_printf(m, "max keysize : %u\n", + alg->cra_cipher.cia_max_keysize); + break; + default: + seq_printf(m, "type : unknown\n"); + break; + } + +out: + seq_putc(m, '\n'); + return 0; +} + +static const struct seq_operations crypto_seq_ops = { + .start = c_start, + .next = c_next, + .stop = c_stop, + .show = c_show +}; + +void __init crypto_init_proc(void) +{ + proc_create_seq("crypto", 0, NULL, &crypto_seq_ops); +} + +void __exit crypto_exit_proc(void) +{ + remove_proc_entry("crypto", NULL); +} -- cgit v1.3.1