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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id p15-20020a634f4f000000b00429c5270710sm166610pgl.1.2022.10.28.19.54.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 28 Oct 2022 19:54:34 -0700 (PDT) From: Kees Cook To: Alexei Starovoitov Cc: Kees Cook , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH bpf-next v2 3/3] bpf/verifier: Take advantage of full allocation sizes Date: Fri, 28 Oct 2022 19:54:32 -0700 Message-Id: <20221029025433.2533810-3-keescook@chromium.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20221029024444.gonna.633-kees@kernel.org> References: <20221029024444.gonna.633-kees@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3544; h=from:subject; bh=kUtgUSzjHG/StpxeZ/gAkJuSWQ81P7If0wKJuguKsQA=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBjXJXoKq5ZWOaEe0w9wu2rU5+gTlHcFnfDONzx5rl8 2MO2kVmJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCY1yV6AAKCRCJcvTf3G3AJjZFEA CbaiZHl1X/Eo7Q6u7OrXXEEu/Fc8P8Egz+2f9weQmvTFT6k8pHEJ646zRGYaElHNuF8dWLLFMJzM1Y uArHQVBqs6LQJ42PuY5l3YGl7j7pmWZwLgscvoR5jyYaXK+/r4zeRdhSbld8X/9cqZ6Jxk8SiPWveK dR/nJPs+tNkPLMdmyWbiEcz5A5+/tAzCBLmZjrgFBEokROEOl+TXx4IIpQbyqgzIDH3+gZ70I1NUhW lPjsvBvh52LVVOaWPV+GLV49VL/tK9veQLcWdWjSMzbnibeWn/xi9OCf94VNP/sAud9eO3w2PFBOij dA4dB88NxOwPgBSoN72V20mybNtqDdfmFCsI3osTyRAdnS+aFgUZ46I72yHpxd016UXEu6QcEUoTgu hKZz6nCyDNN/LfR5C6KER5YAYDzU+MC2uVFAdvE8GeabTsB5cO9kmujEadXdzd4j3C/ZCm6NsUSXG8 LtqGbSpbXDkuteqDDR8dhqIwYkp1t6sajZpOkWVSrKCyEaP65KGhzNwurPBOwlkjyg/K1aQxVys/l4 WVq86oBHhGxemD+KPFGaiLNBxljDw59+kpBi/I8VyCjT7lfHHIqmjFTKNREDkjg5izXZHA9wWJEJ7z CXrUKoUSAdUN08z2u+RbVOxApyfeLHAPi9Jty6yKPofgiYJneRRiZCO0gQjg== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Since the full kmalloc bucket size is being explicitly allocated, pass back the resulting details to take advantage of the full size so that reallocation checking will be needed less frequently. Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: John Fastabend Cc: Andrii Nakryiko Cc: Martin KaFai Lau Cc: Song Liu Cc: Yonghong Song Cc: KP Singh Cc: Stanislav Fomichev Cc: Hao Luo Cc: Jiri Olsa Cc: bpf@vger.kernel.org Signed-off-by: Kees Cook --- kernel/bpf/verifier.c | 27 ++++++++++++++++----------- 1 file changed, 16 insertions(+), 11 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 1c040d27b8f6..e58b554e862b 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1020,20 +1020,23 @@ static void *copy_array(void *dst, const void *src, size_t n, size_t size, gfp_t return dst ? dst : ZERO_SIZE_PTR; } -/* resize an array from old_n items to new_n items. the array is reallocated if it's too - * small to hold new_n items. new items are zeroed out if the array grows. +/* Resize an array from old_n items to *new_n items. The array is + * reallocated if it's too small to hold *new_n items. New items are + * zeroed out if the array grows. Allocation is rounded up to next kmalloc + * bucket size to reduce frequency of resizing. *new_n contains the new + * total number of items that will fit. * - * Contrary to krealloc_array, does not free arr if new_n is zero. + * Contrary to krealloc, does not free arr if new_n is zero. */ -static void *realloc_array(void *arr, size_t old_n, size_t new_n, size_t size) +static void *realloc_array(void *arr, size_t old_n, size_t *new_n, size_t size) { size_t alloc_size; void *new_arr; - if (!new_n || old_n == new_n) + if (!new_n || !*new_n || old_n == *new_n) goto out; - alloc_size = kmalloc_size_roundup(size_mul(new_n, size)); + alloc_size = kmalloc_size_roundup(size_mul(*new_n, size)); new_arr = krealloc(arr, alloc_size, GFP_KERNEL); if (!new_arr) { kfree(arr); @@ -1041,8 +1044,9 @@ static void *realloc_array(void *arr, size_t old_n, size_t new_n, size_t size) } arr = new_arr; - if (new_n > old_n) - memset(arr + old_n * size, 0, (new_n - old_n) * size); + *new_n = alloc_size / size; + if (*new_n > old_n) + memset(arr + old_n * size, 0, (*new_n - old_n) * size); out: return arr ? arr : ZERO_SIZE_PTR; @@ -1074,7 +1078,7 @@ static int copy_stack_state(struct bpf_func_state *dst, const struct bpf_func_st static int resize_reference_state(struct bpf_func_state *state, size_t n) { - state->refs = realloc_array(state->refs, state->acquired_refs, n, + state->refs = realloc_array(state->refs, state->acquired_refs, &n, sizeof(struct bpf_reference_state)); if (!state->refs) return -ENOMEM; @@ -1090,11 +1094,12 @@ static int grow_stack_state(struct bpf_func_state *state, int size) if (old_n >= n) return 0; - state->stack = realloc_array(state->stack, old_n, n, sizeof(struct bpf_stack_state)); + state->stack = realloc_array(state->stack, old_n, &n, + sizeof(struct bpf_stack_state)); if (!state->stack) return -ENOMEM; - state->allocated_stack = size; + state->allocated_stack = n * BPF_REG_SIZE; return 0; }