Similar to kmemdup(), but support large amount of bytes with kvmalloc() and does *not* guarantee that the result will be physically contiguous. Use only in cases where kvmalloc() is needed and free it with kvfree(). Also adapt policy_unpack.c in case someone bisect into this. Suggested-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Signed-off-by: Hao Sun <sunhao.th@xxxxxxxxx> --- This pattern has been used in several places and we're also going to do this[1], seems reasonable to add this so that bpf and in future others could make use of it. v1 -> v2 adapt policy_unpack.c to fix compile error [1] https://lore.kernel.org/bpf/7d274284-0fcc-061c-582e-3dfb629c6a44@xxxxxxxxxxxxx/T/#t --- include/linux/string.h | 1 + mm/util.c | 24 +++++++++++++++++++++++- security/apparmor/policy_unpack.c | 11 +---------- 3 files changed, 25 insertions(+), 11 deletions(-) diff --git a/include/linux/string.h b/include/linux/string.h index db28802ab0a6..c062c581a98b 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -177,6 +177,7 @@ extern char *kstrdup(const char *s, gfp_t gfp) __malloc; extern const char *kstrdup_const(const char *s, gfp_t gfp); extern char *kstrndup(const char *s, size_t len, gfp_t gfp); extern void *kmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2); +extern void *kvmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2); extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp); extern char **argv_split(gfp_t gfp, const char *str, int *argcp); diff --git a/mm/util.c b/mm/util.c index b56c92fb910f..cec9327b27b4 100644 --- a/mm/util.c +++ b/mm/util.c @@ -120,7 +120,8 @@ EXPORT_SYMBOL(kstrndup); * @len: memory region length * @gfp: GFP mask to use * - * Return: newly allocated copy of @src or %NULL in case of error + * Return: newly allocated copy of @src or %NULL in case of error, + * result is physically contiguous. Use kfree() to free. */ void *kmemdup(const void *src, size_t len, gfp_t gfp) { @@ -133,6 +134,27 @@ void *kmemdup(const void *src, size_t len, gfp_t gfp) } EXPORT_SYMBOL(kmemdup); +/** + * kvmemdup - duplicate region of memory + * + * @src: memory region to duplicate + * @len: memory region length + * @gfp: GFP mask to use + * + * Return: newly allocated copy of @src or %NULL in case of error, + * result may be not physically contiguous. Use kvfree() to free. + */ +void *kvmemdup(const void *src, size_t len, gfp_t gfp) +{ + void *p; + + p = kvmalloc(len, gfp); + if (p) + memcpy(p, src, len); + return p; +} +EXPORT_SYMBOL(kvmemdup); + /** * kmemdup_nul - Create a NUL-terminated string from unterminated data * @s: The data to stringify diff --git a/security/apparmor/policy_unpack.c b/security/apparmor/policy_unpack.c index 66915653108c..5e9949832af6 100644 --- a/security/apparmor/policy_unpack.c +++ b/security/apparmor/policy_unpack.c @@ -161,15 +161,6 @@ VISIBLE_IF_KUNIT bool aa_inbounds(struct aa_ext *e, size_t size) } EXPORT_SYMBOL_IF_KUNIT(aa_inbounds); -static void *kvmemdup(const void *src, size_t len) -{ - void *p = kvmalloc(len, GFP_KERNEL); - - if (p) - memcpy(p, src, len); - return p; -} - /** * aa_unpack_u16_chunk - test and do bounds checking for a u16 size based chunk * @e: serialized data read head (NOT NULL) @@ -1027,7 +1018,7 @@ static struct aa_profile *unpack_profile(struct aa_ext *e, char **ns_name) data->key = key; data->size = aa_unpack_blob(e, &data->data, NULL); - data->data = kvmemdup(data->data, data->size); + data->data = kvmemdup(data->data, data->size, GFP_KERNEL); if (data->size && !data->data) { kfree_sensitive(data->key); kfree_sensitive(data); base-commit: b6bb9676f2165d518b35ba3bea5f1fcfc0d969bf -- 2.39.0
