From 9c4c5a24c85585fb8904bd2872501cd8181b3854 Mon Sep 17 00:00:00 2001 From: Denis Efremov Date: Fri, 1 May 2020 16:44:14 +0300 Subject: floppy: add FD_AUTODETECT_SIZE define for struct floppy_drive_params Use FD_AUTODETECT_SIZE for autodetect buffer size in struct floppy_drive_params instead of a magic number. Link: https://lore.kernel.org/r/20200501134416.72248-3-efremov@linux.com Reviewed-by: Christoph Hellwig Signed-off-by: Denis Efremov --- include/uapi/linux/fd.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'include/uapi/linux/fd.h') diff --git a/include/uapi/linux/fd.h b/include/uapi/linux/fd.h index 90fb94712c41..3f6b7be4c096 100644 --- a/include/uapi/linux/fd.h +++ b/include/uapi/linux/fd.h @@ -172,7 +172,10 @@ struct floppy_drive_params { * used in succession to try to read the disk. If the FDC cannot lock onto * the disk, the next format is tried. This uses the variable 'probing'. */ - short autodetect[8]; /* autodetected formats */ + +#define FD_AUTODETECT_SIZE 8 + + short autodetect[FD_AUTODETECT_SIZE]; /* autodetected formats */ int checkfreq; /* how often should the drive be checked for disk * changes */ -- cgit v1.3-6-gb490 From bd10a5f3e21b1cb8e2133c1f08b3e8207cee12dd Mon Sep 17 00:00:00 2001 From: Denis Efremov Date: Fri, 1 May 2020 16:44:15 +0300 Subject: floppy: add defines for sizes of cmd & reply buffers of floppy_raw_cmd Use FD_RAW_CMD_SIZE, FD_RAW_REPLY_SIZE defines instead of magic numbers for cmd & reply buffers of struct floppy_raw_cmd. Remove local to floppy.c MAX_REPLIES define, as it is now FD_RAW_REPLY_SIZE. FD_RAW_CMD_FULLSIZE added as we allow command to also fill reply_count and reply fields. Link: https://lore.kernel.org/r/20200501134416.72248-4-efremov@linux.com Reviewed-by: Christoph Hellwig Signed-off-by: Denis Efremov --- drivers/block/floppy.c | 19 +++++-------------- include/uapi/linux/fd.h | 14 ++++++++++++-- 2 files changed, 17 insertions(+), 16 deletions(-) (limited to 'include/uapi/linux/fd.h') diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index b82b3d38b834..9e098d53b046 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -337,8 +337,7 @@ static bool initialized; /* * globals used by 'result()' */ -#define MAX_REPLIES 16 -static unsigned char reply_buffer[MAX_REPLIES]; +static unsigned char reply_buffer[FD_RAW_REPLY_SIZE]; static int inr; /* size of reply buffer, when called from interrupt */ #define ST0 0 #define ST1 1 @@ -1162,7 +1161,7 @@ static int result(int fdc) int i; int status = 0; - for (i = 0; i < MAX_REPLIES; i++) { + for (i = 0; i < FD_RAW_REPLY_SIZE; i++) { status = wait_til_ready(fdc); if (status < 0) break; @@ -3079,7 +3078,7 @@ static void raw_cmd_done(int flag) raw_cmd->flags |= FD_RAW_HARDFAILURE; } else { raw_cmd->reply_count = inr; - if (raw_cmd->reply_count > MAX_REPLIES) + if (raw_cmd->reply_count > FD_RAW_REPLY_SIZE) raw_cmd->reply_count = 0; for (i = 0; i < raw_cmd->reply_count; i++) raw_cmd->reply[i] = reply_buffer[i]; @@ -3190,18 +3189,10 @@ loop: if (ret) return -EFAULT; param += sizeof(struct floppy_raw_cmd); - if (ptr->cmd_count > 33) - /* the command may now also take up the space - * initially intended for the reply & the - * reply count. Needed for long 82078 commands - * such as RESTORE, which takes ... 17 command - * bytes. Murphy's law #137: When you reserve - * 16 bytes for a structure, you'll one day - * discover that you really need 17... - */ + if (ptr->cmd_count > FD_RAW_CMD_FULLSIZE) return -EINVAL; - for (i = 0; i < 16; i++) + for (i = 0; i < FD_RAW_REPLY_SIZE; i++) ptr->reply[i] = 0; ptr->resultcode = 0; diff --git a/include/uapi/linux/fd.h b/include/uapi/linux/fd.h index 3f6b7be4c096..2e9c2c1c18e6 100644 --- a/include/uapi/linux/fd.h +++ b/include/uapi/linux/fd.h @@ -360,10 +360,20 @@ struct floppy_raw_cmd { int buffer_length; /* length of allocated buffer */ unsigned char rate; + +#define FD_RAW_CMD_SIZE 16 +#define FD_RAW_REPLY_SIZE 16 +#define FD_RAW_CMD_FULLSIZE (FD_RAW_CMD_SIZE + 1 + FD_RAW_REPLY_SIZE) + + /* The command may take up the space initially intended for the reply + * and the reply count. Needed for long 82078 commands such as RESTORE, + * which takes 17 command bytes. + */ + unsigned char cmd_count; - unsigned char cmd[16]; + unsigned char cmd[FD_RAW_CMD_SIZE]; unsigned char reply_count; - unsigned char reply[16]; + unsigned char reply[FD_RAW_REPLY_SIZE]; int track; int resultcode; -- cgit v1.3-6-gb490 From 0836275df4db20daf040fff5d9a1da89c4c08a85 Mon Sep 17 00:00:00 2001 From: Denis Efremov Date: Fri, 1 May 2020 16:44:16 +0300 Subject: floppy: suppress UBSAN warning in setup_rw_floppy() UBSAN: array-index-out-of-bounds in drivers/block/floppy.c:1521:45 index 16 is out of range for type 'unsigned char [16]' Call Trace: ... setup_rw_floppy+0x5c3/0x7f0 floppy_ready+0x2be/0x13b0 process_one_work+0x2c1/0x5d0 worker_thread+0x56/0x5e0 kthread+0x122/0x170 ret_from_fork+0x35/0x40 From include/uapi/linux/fd.h: struct floppy_raw_cmd { ... unsigned char cmd_count; unsigned char cmd[16]; unsigned char reply_count; unsigned char reply[16]; ... } This out-of-bounds access is intentional. The command in struct floppy_raw_cmd may take up the space initially intended for the reply and the reply count. It is needed for long 82078 commands such as RESTORE, which takes 17 command bytes. Initial cmd size is not enough and since struct setup_rw_floppy is a part of uapi we check that cmd_count is in [0:16+1+16] in raw_cmd_copyin(). The patch adds union with original cmd,reply_count,reply fields and fullcmd field of equivalent size. The cmd accesses are turned to fullcmd where appropriate to suppress UBSAN warning. Link: https://lore.kernel.org/r/20200501134416.72248-5-efremov@linux.com Reviewed-by: Christoph Hellwig Signed-off-by: Denis Efremov --- drivers/block/floppy.c | 4 ++-- include/uapi/linux/fd.h | 11 ++++++++--- 2 files changed, 10 insertions(+), 5 deletions(-) (limited to 'include/uapi/linux/fd.h') diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index 9e098d53b046..064c1acb9f00 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -1070,7 +1070,7 @@ static void setup_DMA(void) if (raw_cmd->length == 0) { print_hex_dump(KERN_INFO, "zero dma transfer size: ", DUMP_PREFIX_NONE, 16, 1, - raw_cmd->cmd, raw_cmd->cmd_count, false); + raw_cmd->fullcmd, raw_cmd->cmd_count, false); cont->done(0); fdc_state[current_fdc].reset = 1; return; @@ -1515,7 +1515,7 @@ static void setup_rw_floppy(void) r = 0; for (i = 0; i < raw_cmd->cmd_count; i++) - r |= output_byte(current_fdc, raw_cmd->cmd[i]); + r |= output_byte(current_fdc, raw_cmd->fullcmd[i]); debugt(__func__, "rw_command"); diff --git a/include/uapi/linux/fd.h b/include/uapi/linux/fd.h index 2e9c2c1c18e6..8b80c63b971c 100644 --- a/include/uapi/linux/fd.h +++ b/include/uapi/linux/fd.h @@ -371,9 +371,14 @@ struct floppy_raw_cmd { */ unsigned char cmd_count; - unsigned char cmd[FD_RAW_CMD_SIZE]; - unsigned char reply_count; - unsigned char reply[FD_RAW_REPLY_SIZE]; + union { + struct { + unsigned char cmd[FD_RAW_CMD_SIZE]; + unsigned char reply_count; + unsigned char reply[FD_RAW_REPLY_SIZE]; + }; + unsigned char fullcmd[FD_RAW_CMD_FULLSIZE]; + }; int track; int resultcode; -- cgit v1.3-6-gb490