diff options
Diffstat (limited to 'mm/kmsan/core.c')
| -rw-r--r-- | mm/kmsan/core.c | 32 |
1 files changed, 15 insertions, 17 deletions
diff --git a/mm/kmsan/core.c b/mm/kmsan/core.c index cf2d70e9c9a5..1ea711786c52 100644 --- a/mm/kmsan/core.c +++ b/mm/kmsan/core.c @@ -43,7 +43,6 @@ void kmsan_internal_task_create(struct task_struct *task) struct thread_info *info = current_thread_info(); __memset(ctx, 0, sizeof(*ctx)); - ctx->allow_reporting = true; kmsan_internal_unpoison_memory(info, sizeof(*info), false); } @@ -160,8 +159,8 @@ depot_stack_handle_t kmsan_internal_chain_origin(depot_stack_handle_t id) * Make sure we have enough spare bits in @id to hold the UAF bit and * the chain depth. */ - BUILD_BUG_ON( - (1 << STACK_DEPOT_EXTRA_BITS) <= (KMSAN_MAX_ORIGIN_DEPTH << 1)); + BUILD_BUG_ON((1 << STACK_DEPOT_EXTRA_BITS) <= + (KMSAN_MAX_ORIGIN_DEPTH << 1)); extra_bits = stack_depot_get_extra_bits(id); depth = kmsan_depth_from_eb(extra_bits); @@ -196,8 +195,7 @@ void kmsan_internal_set_shadow_origin(void *addr, size_t size, int b, u32 origin, bool checked) { u64 address = (u64)addr; - void *shadow_start; - u32 *origin_start; + u32 *shadow_start, *origin_start; size_t pad = 0; KMSAN_WARN_ON(!kmsan_metadata_is_contiguous(addr, size)); @@ -225,8 +223,16 @@ void kmsan_internal_set_shadow_origin(void *addr, size_t size, int b, origin_start = (u32 *)kmsan_get_metadata((void *)address, KMSAN_META_ORIGIN); - for (int i = 0; i < size / KMSAN_ORIGIN_SIZE; i++) - origin_start[i] = origin; + /* + * If the new origin is non-zero, assume that the shadow byte is also non-zero, + * and unconditionally overwrite the old origin slot. + * If the new origin is zero, overwrite the old origin slot iff the + * corresponding shadow slot is zero. + */ + for (int i = 0; i < size / KMSAN_ORIGIN_SIZE; i++) { + if (origin || !shadow_start[i]) + origin_start[i] = origin; + } } struct page *kmsan_vmalloc_to_page_or_null(void *vaddr) @@ -243,8 +249,8 @@ struct page *kmsan_vmalloc_to_page_or_null(void *vaddr) return NULL; } -void kmsan_internal_check_memory(void *addr, size_t size, const void *user_addr, - int reason) +void kmsan_internal_check_memory(void *addr, size_t size, + const void __user *user_addr, int reason) { depot_stack_handle_t cur_origin = 0, new_origin = 0; unsigned long addr64 = (unsigned long)addr; @@ -268,11 +274,9 @@ void kmsan_internal_check_memory(void *addr, size_t size, const void *user_addr, * bytes before, report them. */ if (cur_origin) { - kmsan_enter_runtime(); kmsan_report(cur_origin, addr, size, cur_off_start, pos - 1, user_addr, reason); - kmsan_leave_runtime(); } cur_origin = 0; cur_off_start = -1; @@ -286,11 +290,9 @@ void kmsan_internal_check_memory(void *addr, size_t size, const void *user_addr, * poisoned bytes before, report them. */ if (cur_origin) { - kmsan_enter_runtime(); kmsan_report(cur_origin, addr, size, cur_off_start, pos + i - 1, user_addr, reason); - kmsan_leave_runtime(); } cur_origin = 0; cur_off_start = -1; @@ -306,11 +308,9 @@ void kmsan_internal_check_memory(void *addr, size_t size, const void *user_addr, */ if (cur_origin != new_origin) { if (cur_origin) { - kmsan_enter_runtime(); kmsan_report(cur_origin, addr, size, cur_off_start, pos + i - 1, user_addr, reason); - kmsan_leave_runtime(); } cur_origin = new_origin; cur_off_start = pos + i; @@ -320,10 +320,8 @@ void kmsan_internal_check_memory(void *addr, size_t size, const void *user_addr, } KMSAN_WARN_ON(pos != size); if (cur_origin) { - kmsan_enter_runtime(); kmsan_report(cur_origin, addr, size, cur_off_start, pos - 1, user_addr, reason); - kmsan_leave_runtime(); } } |