7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tianchu Chen commit 7a4ce92d150b9e7ecf1a710a34d8cdeb590d3751 upstream. sprd_platform_compr_open() allocates the stage 0 IRAM buffer (32K data area) and the stage 1 DDR buffer (2M data area) with fixed sizes, but sprd_platform_compr_copy() derives all copy lengths from the user controlled runtime->fragment_size and the write() count, never comparing them against the physical buffer sizes. The compress core only checks fragment_size * fragments for an u32 overflow in snd_compress_check_input(), so a local user can configure a logical buffer of up to ~4GB via SNDRV_COMPRESS_SET_PARAMS, far exceeding the fixed allocations. A fragment_size larger than the 32K IRAM data area makes the stage 0 copy_from_user() overflow past the IRAM allocation, and a buffer_size larger than the 2M DDR buffer makes the wrapping copy at the end of sprd_platform_compr_copy() write fully user controlled data past the buffer. No SNDRV_PCM_TRIGGER_START is needed, a write() in SETUP state reaches the copy callback directly. Reject parameters that do not fit into the fixed buffers in set_params(), and fix the advertised max fragment size: 128K never fitted into the 32K IRAM buffer. The caps values may have been carried over from the qdsp6 driver, which allocates its buffers according to the advertised maxima, unlike this driver. With 32K as max fragment size the advertised limits are self-consistent: 32K * 64 = 2M equals the DDR buffer size. Discovered by Atuin - Automated Vulnerability Discovery Engine. Fixes: cce1396936ef ("ASoC: sprd: Add Spreadtrum audio compress offload support") Cc: stable@vger.kernel.org Assisted-by: LLM Signed-off-by: Tianchu Chen Link: https://patch.msgid.link/4386bc53631b052c1866a91061715b009d98b04f@linux.dev Signed-off-by: Mark Brown Signed-off-by: Greg Kroah-Hartman --- sound/soc/sprd/sprd-pcm-compress.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) --- a/sound/soc/sprd/sprd-pcm-compress.c +++ b/sound/soc/sprd/sprd-pcm-compress.c @@ -17,7 +17,7 @@ /* Default values if userspace does not set */ #define SPRD_COMPR_MIN_FRAGMENT_SIZE SZ_8K -#define SPRD_COMPR_MAX_FRAGMENT_SIZE SZ_128K +#define SPRD_COMPR_MAX_FRAGMENT_SIZE SZ_32K #define SPRD_COMPR_MIN_NUM_FRAGMENTS 4 #define SPRD_COMPR_MAX_NUM_FRAGMENTS 64 @@ -272,6 +272,19 @@ static int sprd_platform_compr_set_param int ret; /* + * The stage 0 IRAM buffer and the stage 1 DDR buffer are allocated + * with fixed sizes at open time, so the requested fragment size and + * fragments must fit into them, otherwise sprd_platform_compr_copy() + * would overflow the buffers. Note the compress core only checks the + * fragment size and fragments against an u32 overflow, not against + * the buffer sizes advertised by get_caps. + */ + if (params->buffer.fragment_size > SPRD_COMPR_IRAM_BUF_SIZE || + (u64)params->buffer.fragment_size * params->buffer.fragments > + SPRD_COMPR_AREA_BUF_SIZE) + return -EINVAL; + + /* * Configure the DMA engine 2-stage transfer mode. Channel 1 set as the * destination channel, and channel 0 set as the source channel, that * means once the source channel's transaction is done, it will trigger