From e5046823f8fa3677341b541a25af2fcb99a5b1e0 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 25 Mar 2026 20:29:20 -0700 Subject: lib/crypto: chacha: Zeroize permuted_state before it leaves scope Since the ChaCha permutation is invertible, the local variable 'permuted_state' is sufficient to compute the original 'state', and thus the key, even after the permutation has been done. While the kernel is quite inconsistent about zeroizing secrets on the stack (and some prominent userspace crypto libraries don't bother at all since it's not guaranteed to work anyway), the kernel does try to do it as a best practice, especially in cases involving the RNG. Thus, explicitly zeroize 'permuted_state' before it goes out of scope. Fixes: c08d0e647305 ("crypto: chacha20 - Add a generic ChaCha20 stream cipher implementation") Cc: stable@vger.kernel.org Acked-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20260326032920.39408-1-ebiggers@kernel.org Signed-off-by: Eric Biggers --- lib/crypto/chacha-block-generic.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'lib') diff --git a/lib/crypto/chacha-block-generic.c b/lib/crypto/chacha-block-generic.c index 77f68de71066..4a6d627580cb 100644 --- a/lib/crypto/chacha-block-generic.c +++ b/lib/crypto/chacha-block-generic.c @@ -87,6 +87,8 @@ void chacha_block_generic(struct chacha_state *state, &out[i * sizeof(u32)]); state->x[12]++; + + chacha_zeroize_state(&permuted_state); } EXPORT_SYMBOL(chacha_block_generic); @@ -110,5 +112,7 @@ void hchacha_block_generic(const struct chacha_state *state, memcpy(&out[0], &permuted_state.x[0], 16); memcpy(&out[4], &permuted_state.x[12], 16); + + chacha_zeroize_state(&permuted_state); } EXPORT_SYMBOL(hchacha_block_generic); -- cgit v1.2.3 From 2598ab9d63f41160c7081998857fef409182933d Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 23 Mar 2026 21:55:16 +0100 Subject: bug: avoid format attribute warning for clang as well Like gcc, clang-22 now also warns about a function that it incorrectly identifies as a printf-style format: lib/bug.c:190:22: error: diagnostic behavior may be improved by adding the 'format(printf, 1, 0)' attribute to the declaration of '__warn_printf' [-Werror,-Wmissing-format-attribute] 179 | static void __warn_printf(const char *fmt, struct pt_regs *regs) | __attribute__((format(printf, 1, 0))) 180 | { 181 | if (!fmt) 182 | return; 183 | 184 | #ifdef HAVE_ARCH_BUG_FORMAT_ARGS 185 | if (regs) { 186 | struct arch_va_list _args; 187 | va_list *args = __warn_args(&_args, regs); 188 | 189 | if (args) { 190 | vprintk(fmt, *args); | ^ Revert the change that added a gcc-specific workaround, and instead add the generic annotation that avoid the warning. Link: https://lkml.kernel.org/r/20260323205534.1284284-1-arnd@kernel.org Fixes: d36067d6ea00 ("bug: Hush suggest-attribute=format for __warn_printf()") Suggested-by: Andy Shevchenko Suggested-by: Brendan Jackman Link: https://lore.kernel.org/all/20251208141618.2805983-1-andriy.shevchenko@linux.intel.com/T/#u Signed-off-by: Arnd Bergmann Reviewed-by: Brendan Jackman Reviewed-by: Andy Shevchenko Cc: Bill Wendling Cc: Ingo Molnar Cc: Justin Stitt Cc: Nathan Chancellor Cc: Peter Zijlstra Signed-off-by: Andrew Morton --- lib/bug.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) (limited to 'lib') diff --git a/lib/bug.c b/lib/bug.c index 623c467a8b76..aab9e6a40c5f 100644 --- a/lib/bug.c +++ b/lib/bug.c @@ -173,10 +173,8 @@ struct bug_entry *find_bug(unsigned long bugaddr) return module_find_bug(bugaddr); } -__diag_push(); -__diag_ignore(GCC, all, "-Wsuggest-attribute=format", - "Not a valid __printf() conversion candidate."); -static void __warn_printf(const char *fmt, struct pt_regs *regs) +static __printf(1, 0) +void __warn_printf(const char *fmt, struct pt_regs *regs) { if (!fmt) return; @@ -195,7 +193,6 @@ static void __warn_printf(const char *fmt, struct pt_regs *regs) printk("%s", fmt); } -__diag_pop(); static enum bug_trap_type __report_bug(struct bug_entry *bug, unsigned long bugaddr, struct pt_regs *regs) { -- cgit v1.2.3