From: "Michael S. Tsirkin" Date: Wed, 12 Nov 2014 11:44:39 +0200 Subject: [PATCH] migration: fix parameter validation on ram load During migration, the values read from migration stream during ram load are not validated. Especially offset in host_from_stream_offset() and also the length of the writes in the callers of said function. To fix this, we need to make sure that the [offset, offset + length] range fits into one of the allocated memory regions. Validating addr < len should be sufficient since data seems to always be managed in TARGET_PAGE_SIZE chunks. Fixes: CVE-2014-7840 Note: follow-up patches add extra checks on each block->host access. Signed-off-by: Michael S. Tsirkin Reviewed-by: Paolo Bonzini Reviewed-by: Dr. David Alan Gilbert Signed-off-by: Amit Shah (cherry picked from commit 0be839a2701369f669532ea5884c15bead1c6e08) Conflicts: arch_init.c --- arch_init.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch_init.c b/arch_init.c index 23151b3..b6f7958 100644 --- a/arch_init.c +++ b/arch_init.c @@ -816,8 +816,8 @@ static inline void *host_from_stream_offset(QEMUFile *f, uint8_t len; if (flags & RAM_SAVE_FLAG_CONTINUE) { - if (!block) { - fprintf(stderr, "Ack, bad migration stream!\n"); + if (!block || block->length <= offset) { + fprintf(stderr, "Ack, bad migration stream!"); return NULL; } @@ -829,8 +829,9 @@ static inline void *host_from_stream_offset(QEMUFile *f, id[len] = 0; QTAILQ_FOREACH(block, &ram_list.blocks, next) { - if (!strncmp(id, block->idstr, sizeof(id))) + if (!strncmp(id, block->idstr, sizeof(id)) && block->length > offset) { return memory_region_get_ram_ptr(block->mr) + offset; + } } fprintf(stderr, "Can't find block %s!\n", id);