kernel/linux.git/security/integrity/ima/ima_crypto.c, branch linux-7.1.y

ima: remove buggy support for asynchronous hashes

2026-03-17T22:53:49+00:00

IMA computes hashes using the crypto_shash or crypto_ahash API. The latter is used only when ima.ahash_minsize is set on the command line, and its purpose is ostensibly to make the hash computation faster. However, going off the CPU to a crypto engine and back again is actually quite slow, especially compared with the acceleration that is built into modern CPUs and the kernel now enables by default for most algorithms. Typical performance results for SHA-256 on a modern platform can be found at https://lore.kernel.org/linux-crypto/20250615184638.GA1480@sol/ Partly for this reason, several other kernel subsystems have already dropped support for the crypto_ahash API. The other problem with crypto_ahash is that bugs are also common, not just in the underlying drivers, but also in the code using it, since it is very difficult to use correctly. Just from a quick review, here are some of the bugs I noticed in IMA's ahash code: - [Use after free] ima_alloc_atfm() isn't thread-safe and can trigger a use-after-free if multiple threads try to initialize the global ima_ahash_tfm at the same time. - [Deadlock] If only one buffer is allocated and there is an error reading from the file, then ahash_wait() is executed twice, causing a deadlock in wait_for_completion(). - [Crash or incorrect hash computed] calc_buffer_ahash_atfm() is sometimes passed stack buffers which can be vmalloc addresses, but it puts them in a scatterlist assuming they are linear addresses. This causes the hashing to be done on the wrong physical address. - [Truncation to 32-bit length] ima_alloc_pages() incorrectly assumes an loff_t value fits in an unsigned long. calc_buffer_ahash_atfm() incorrectly assumes that a loff_t value fits in an unsigned int. So, not exactly a great track record so far, even disregarding driver bugs which are an even larger problem. Fortunately, in practice it's unlikely that many users are actually setting the ima.ahash_minsize kernel command-line parameter which enables this code. However, given that this code is almost certainly no longer useful (if it ever was), let's just remove it instead of attempting to fix all these issues. Signed-off-by: Eric Biggers Acked-by: Dmitry Kasatkin Signed-off-by: Mimi Zohar

ima: check return value of crypto_shash_final() in boot aggregate

2026-03-09T14:57:49+00:00

The return value of crypto_shash_final() is not checked in ima_calc_boot_aggregate_tfm(). If the hash finalization fails, the function returns success and a corrupted boot aggregate digest could be used for IMA measurements. Capture the return value and propagate any error to the caller. Fixes: 76bb28f6126f ("ima: use new crypto_shash API instead of old crypto_hash") Signed-off-by: Daniel Hodges Reviewed-by: Roberto Sassu Signed-off-by: Mimi Zohar

ima: Define and use a digest_size field in the ima_algo_desc structure

2026-03-08T12:26:08+00:00

Add the digest_size field to the ima_algo_desc structure to determine the digest size from the correct source. If the hash algorithm is among allocated PCR banks, take the value from the TPM bank info (equal to the value from the crypto subsystem if the TPM algorithm is supported by it; otherwise, not exceding the size of the digest buffer in the tpm_digest structure, used by IMA). If the hash algorithm is SHA1, use the predefined value. Lastly, if the hash algorithm is the default one but not among the PCR banks, take the digest size from the crypto subsystem (the default hash algorithm is checked when parsing the ima_hash= command line option). Finally, use the new information to correctly show the template digest in ima_measurements_show() and ima_ascii_measurements_show(). Link: https://github.com/linux-integrity/linux/issues/14 Signed-off-by: Roberto Sassu Signed-off-by: Mimi Zohar

Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses

2026-02-22T16:26:33+00:00

Conversion performed via this Coccinelle script: // SPDX-License-Identifier: GPL-2.0-only // Options: --include-headers-for-types --all-includes --include-headers --keep-comments virtual patch @gfp depends on patch && !(file in "tools") && !(file in "samples")@ identifier ALLOC = {kmalloc_obj,kmalloc_objs,kmalloc_flex, kzalloc_obj,kzalloc_objs,kzalloc_flex, kvmalloc_obj,kvmalloc_objs,kvmalloc_flex, kvzalloc_obj,kvzalloc_objs,kvzalloc_flex}; @@ ALLOC(... - , GFP_KERNEL ) $ make coccicheck MODE=patch COCCI=gfp.cocci Build and boot tested x86_64 with Fedora 42's GCC and Clang: Linux version 6.19.0+ (user@host) (gcc (GCC) 15.2.1 20260123 (Red Hat 15.2.1-7), GNU ld version 2.44-12.fc42) #1 SMP PREEMPT_DYNAMIC 1970-01-01 Linux version 6.19.0+ (user@host) (clang version 20.1.8 (Fedora 20.1.8-4.fc42), LLD 20.1.8) #1 SMP PREEMPT_DYNAMIC 1970-01-01 Signed-off-by: Kees Cook Signed-off-by: Linus Torvalds

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

ima: add crypto agility support for template-hash algorithm

2024-04-12T13:59:04+00:00

The template hash showed by the ascii_runtime_measurements and binary_runtime_measurements is the one calculated using sha1 and there is no possibility to change this value, despite the fact that the template hash is calculated using the hash algorithms corresponding to all the PCR banks configured in the TPM. Add the support to retrieve the ima log with the template data hash calculated with a specific hash algorithm. Add a new file in the securityfs ima directory for each hash algo configured in a PCR bank of the TPM. Each new file has the name with the following structure: {binary, ascii}_runtime_measurements_ Legacy files are kept, to avoid breaking existing applications, but as symbolic links which point to {binary, ascii}_runtime_measurements_sha1 files. These two files are created even if a TPM chip is not detected or the sha1 bank is not configured in the TPM. As example, in the case a TPM chip is present and sha256 is the only configured PCR bank, the listing of the securityfs ima directory is the following: lr--r--r-- [...] ascii_runtime_measurements -> ascii_runtime_measurements_sha1 -r--r----- [...] ascii_runtime_measurements_sha1 -r--r----- [...] ascii_runtime_measurements_sha256 lr--r--r-- [...] binary_runtime_measurements -> binary_runtime_measurements_sha1 -r--r----- [...] binary_runtime_measurements_sha1 -r--r----- [...] binary_runtime_measurements_sha256 --w------- [...] policy -r--r----- [...] runtime_measurements_count -r--r----- [...] violations Signed-off-by: Enrico Bravi Signed-off-by: Silvia Sisinni Reviewed-by: Roberto Sassu Signed-off-by: Mimi Zohar

mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER

2024-01-08T23:27:15+00:00

commit 23baf831a32c ("mm, treewide: redefine MAX_ORDER sanely") has changed the definition of MAX_ORDER to be inclusive. This has caused issues with code that was not yet upstream and depended on the previous definition. To draw attention to the altered meaning of the define, rename MAX_ORDER to MAX_PAGE_ORDER. Link: https://lkml.kernel.org/r/20231228144704.14033-2-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov Cc: Linus Torvalds Signed-off-by: Andrew Morton

mm, treewide: redefine MAX_ORDER sanely

2023-04-06T02:42:46+00:00

MAX_ORDER currently defined as number of orders page allocator supports: user can ask buddy allocator for page order between 0 and MAX_ORDER-1. This definition is counter-intuitive and lead to number of bugs all over the kernel. Change the definition of MAX_ORDER to be inclusive: the range of orders user can ask from buddy allocator is 0..MAX_ORDER now. [kirill@shutemov.name: fix min() warning] Link: https://lkml.kernel.org/r/20230315153800.32wib3n5rickolvh@box [akpm@linux-foundation.org: fix another min_t warning] [kirill@shutemov.name: fixups per Zi Yan] Link: https://lkml.kernel.org/r/20230316232144.b7ic4cif4kjiabws@box.shutemov.name [akpm@linux-foundation.org: fix underlining in docs] Link: https://lore.kernel.org/oe-kbuild-all/202303191025.VRCTk6mP-lkp@intel.com/ Link: https://lkml.kernel.org/r/20230315113133.11326-11-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov Reviewed-by: Michael Ellerman [powerpc] Cc: "Kirill A. Shutemov" Cc: Zi Yan Signed-off-by: Andrew Morton

ima: Fix potential memory leak in ima_init_crypto()

2022-07-13T14:13:58+00:00

On failure to allocate the SHA1 tfm, IMA fails to initialize and exits without freeing the ima_algo_array. Add the missing kfree() for ima_algo_array to avoid the potential memory leak. Signed-off-by: Jianglei Nie Fixes: 6d94809af6b0 ("ima: Allocate and initialize tfm for each PCR bank") Signed-off-by: Mimi Zohar

ima/evm: Fix type mismatch

2021-06-08T20:29:10+00:00

The endianness of a variable written to the measurement list cannot be determined at compile time, as it depends on the value of the ima_canonical_fmt global variable (set through a kernel option with the same name if the machine is big endian). If ima_canonical_fmt is false, the endianness of a variable is the same as the machine; if ima_canonical_fmt is true, the endianness is little endian. The warning arises due to this type of instruction: var = cpu_to_leXX(var) which tries to assign a value in little endian to a variable with native endianness (little or big endian). Given that the variables set with this instruction are not used in any operation but just written to a buffer, it is safe to force the type of the value being set to be the same of the type of the variable with: var = (__force )cpu_to_leXX(var) Reported-by: kernel test robot Signed-off-by: Roberto Sassu Signed-off-by: Mimi Zohar