liblzma: Validate encoder arguments better.
The biggest problem was that the integrity check type
wasn't validated, and e.g. lzma_easy_buffer_encode()
would create a corrupt .xz Stream if given an unsupported
Check ID. Luckily applications don't usually try to use
an unsupport Check ID, so this bug is unlikely to cause
many real-world problems.
diff --git a/src/liblzma/common/block_buffer_encoder.c b/src/liblzma/common/block_buffer_encoder.c
index a8f71c2..519c6a6 100644
--- a/src/liblzma/common/block_buffer_encoder.c
+++ b/src/liblzma/common/block_buffer_encoder.c
@@ -226,16 +226,23 @@
const uint8_t *in, size_t in_size,
uint8_t *out, size_t *out_pos, size_t out_size)
{
- // Sanity checks
- if (block == NULL || block->filters == NULL
- || (in == NULL && in_size != 0) || out == NULL
+ // Validate the arguments.
+ if (block == NULL || (in == NULL && in_size != 0) || out == NULL
|| out_pos == NULL || *out_pos > out_size)
return LZMA_PROG_ERROR;
- // Check the version field.
+ // The contents of the structure may depend on the version so
+ // check the version before validating the contents of *block.
if (block->version != 0)
return LZMA_OPTIONS_ERROR;
+ if ((unsigned int)(block->check) > LZMA_CHECK_ID_MAX
+ || block->filters == NULL)
+ return LZMA_PROG_ERROR;
+
+ if (!lzma_check_is_supported(block->check))
+ return LZMA_UNSUPPORTED_CHECK;
+
// Size of a Block has to be a multiple of four, so limit the size
// here already. This way we don't need to check it again when adding
// Block Padding.
@@ -243,8 +250,7 @@
// Get the size of the Check field.
const size_t check_size = lzma_check_size(block->check);
- if (check_size == UINT32_MAX)
- return LZMA_PROG_ERROR;
+ assert(check_size != UINT32_MAX);
// Reserve space for the Check field.
if (out_size - *out_pos <= check_size)
diff --git a/src/liblzma/common/block_encoder.c b/src/liblzma/common/block_encoder.c
index ca51523..b34c501 100644
--- a/src/liblzma/common/block_encoder.c
+++ b/src/liblzma/common/block_encoder.c
@@ -161,6 +161,11 @@
{
lzma_next_coder_init(&lzma_block_encoder_init, next, allocator);
+ if (block == NULL)
+ return LZMA_PROG_ERROR;
+
+ // The contents of the structure may depend on the version so
+ // check the version first.
if (block->version != 0)
return LZMA_OPTIONS_ERROR;
diff --git a/src/liblzma/common/stream_buffer_encoder.c b/src/liblzma/common/stream_buffer_encoder.c
index 0542c30..2450ee2 100644
--- a/src/liblzma/common/stream_buffer_encoder.c
+++ b/src/liblzma/common/stream_buffer_encoder.c
@@ -51,6 +51,9 @@
|| out_pos_ptr == NULL || *out_pos_ptr > out_size)
return LZMA_PROG_ERROR;
+ if (!lzma_check_is_supported(check))
+ return LZMA_UNSUPPORTED_CHECK;
+
// Note for the paranoids: Index encoder prevents the Stream from
// getting too big and still being accepted with LZMA_OK, and Block
// encoder catches if the input is too big. So we don't need to
