From 31e8e269a9351f867416b249d40e41d4e1aa5cad Mon Sep 17 00:00:00 2001 From: =?utf8?q?Pali=20Roh=C3=A1r?= Date: Sun, 23 Dec 2018 11:40:12 +0100 Subject: [PATCH] avinfo: Fix buffer overflow when parsing broken/malicious data Check size of buffer prior casting it to struct. Change-Id: I8a3ee8d8bf2dfef7b37a7075f2062804268de639 Signed-off-by: himanshu --- tools/avinfo.c | 91 +++++++++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 71 insertions(+), 20 deletions(-) diff --git a/tools/avinfo.c b/tools/avinfo.c index 31c4e10..47fa1d2 100755 --- a/tools/avinfo.c +++ b/tools/avinfo.c @@ -167,10 +167,15 @@ struct avdtp_content_protection_capability { uint8_t data[0]; } __attribute__ ((packed)); -static void print_aptx(a2dp_aptx_t *aptx) +static void print_aptx(a2dp_aptx_t *aptx, uint8_t size) { printf("\t\tVendor Specific Value (aptX)"); + if (size < sizeof(*aptx)) { + printf(" (broken)\n"); + return; + } + printf("\n\t\t\tFrequencies: "); if (aptx->frequency & APTX_SAMPLING_FREQ_16000) printf("16kHz "); @@ -190,20 +195,33 @@ static void print_aptx(a2dp_aptx_t *aptx) printf("\n"); } -static void print_ldac(a2dp_ldac_t *ldac) +static void print_ldac(a2dp_ldac_t *ldac, uint8_t size) { printf("\t\tVendor Specific Value (LDAC)"); + if (size < sizeof(*ldac)) { + printf(" (broken)\n"); + return; + } + printf("\n\t\t\tUnknown: %02x %02x", ldac->unknown[0], ldac->unknown[1]); printf("\n"); } -static void print_vendor(a2dp_vendor_codec_t *vendor) +static void print_vendor(a2dp_vendor_codec_t *vendor, uint8_t size) { - uint32_t vendor_id = btohl(vendor->vendor_id); - uint16_t codec_id = btohs(vendor->codec_id); + uint32_t vendor_id; + uint16_t codec_id; + + if (size < sizeof(*vendor)) { + printf("\tMedia Codec: Vendor Specific A2DP Codec (broken)"); + return; + } + + vendor_id = btohl(vendor->vendor_id); + codec_id = btohs(vendor->codec_id); printf("\tMedia Codec: Vendor Specific A2DP Codec"); @@ -212,15 +230,22 @@ static void print_vendor(a2dp_vendor_codec_t *vendor) printf("\n\t\tVendor Specific Codec ID 0x%04x\n", codec_id); if (vendor_id == APTX_VENDOR_ID && codec_id == APTX_CODEC_ID) - print_aptx((void *) vendor); + print_aptx((void *) vendor, size); else if (vendor_id == LDAC_VENDOR_ID && codec_id == LDAC_CODEC_ID) - print_ldac((void *) vendor); + print_ldac((void *) vendor, size); } -static void print_mpeg24(a2dp_aac_t *aac) +static void print_mpeg24(a2dp_aac_t *aac, uint8_t size) { - unsigned freq = AAC_GET_FREQUENCY(*aac); - unsigned bitrate = AAC_GET_BITRATE(*aac); + unsigned int freq, bitrate; + + if (size < sizeof(*aac)) { + printf("\tMedia Codec: MPEG24 (broken)\n"); + return; + } + + freq = AAC_GET_FREQUENCY(*aac); + bitrate = AAC_GET_BITRATE(*aac); printf("\tMedia Codec: MPEG24\n\t\tObject Types: "); @@ -270,8 +295,13 @@ static void print_mpeg24(a2dp_aac_t *aac) printf("\n\t\tVBR: %s", aac->vbr ? "Yes\n" : "No\n"); } -static void print_mpeg12(a2dp_mpeg_t *mpeg) +static void print_mpeg12(a2dp_mpeg_t *mpeg, uint8_t size) { + if (size < sizeof(*mpeg)) { + printf("\tMedia Codec: MPEG12 (broken)\n"); + return; + } + printf("\tMedia Codec: MPEG12\n\t\tChannel Modes: "); if (mpeg->channel_mode & MPEG_CHANNEL_MODE_MONO) @@ -351,8 +381,13 @@ static void print_mpeg12(a2dp_mpeg_t *mpeg) printf("RFC-2250\n"); } -static void print_sbc(a2dp_sbc_t *sbc) +static void print_sbc(a2dp_sbc_t *sbc, uint8_t size) { + if (size < sizeof(*sbc)) { + printf("\tMedia Codec: SBC (broken)\n"); + return; + } + printf("\tMedia Codec: SBC\n\t\tChannel Modes: "); if (sbc->channel_mode & SBC_CHANNEL_MODE_MONO) @@ -394,20 +429,27 @@ static void print_sbc(a2dp_sbc_t *sbc) sbc->min_bitpool, sbc->max_bitpool); } -static void print_media_codec(struct avdtp_media_codec_capability *cap) +static void print_media_codec( + struct avdtp_media_codec_capability *cap, + uint8_t size) { + if (size < sizeof(*cap)) { + printf("\tMedia Codec: Unknown (broken)\n"); + return; + } + switch (cap->media_codec_type) { case A2DP_CODEC_SBC: - print_sbc((void *) cap->data); + print_sbc((void *) cap->data, size - 2); break; case A2DP_CODEC_MPEG12: - print_mpeg12((void *) cap->data); + print_mpeg12((void *) cap->data, size - 2); break; case A2DP_CODEC_MPEG24: - print_mpeg24((void *) cap->data); + print_mpeg24((void *) cap->data, size - 2); break; case A2DP_CODEC_VENDOR: - print_vendor((void *) cap->data); + print_vendor((void *) cap->data, size - 2); break; default: printf("\tMedia Codec: Unknown\n"); @@ -415,10 +457,16 @@ static void print_media_codec(struct avdtp_media_codec_capability *cap) } static void print_content_protection( - struct avdtp_content_protection_capability *cap) + struct avdtp_content_protection_capability *cap, + uint8_t size) { printf("\tContent Protection: "); + if (size < sizeof(*cap)) { + printf("Unknown (broken)\n"); + return; + } + switch (btohs(cap->content_protection_type)) { case AVDTP_CONTENT_PROTECTION_TYPE_DTCP: printf("DTCP"); @@ -452,13 +500,16 @@ static void print_caps(void *data, int size) case AVDTP_REPORTING: case AVDTP_RECOVERY: case AVDTP_MULTIPLEXING: + default: /* FIXME: Add proper functions */ + printf("\tUnknown category: %d\n", cap->category); break; case AVDTP_MEDIA_CODEC: - print_media_codec((void *) cap->data); + print_media_codec((void *) cap->data, cap->length); break; case AVDTP_CONTENT_PROTECTION: - print_content_protection((void *) cap->data); + print_content_protection((void *) cap->data, + cap->length); break; } -- 2.7.4