block: fix potential invalid pointer dereference in blk_add_partition

[ Upstream commit 26e197b7f9240a4ac301dd0ad520c0c697c2ea7d ]

The blk_add_partition() function initially used a single if-condit

block: fix potential invalid pointer dereference in blk_add_partition

[ Upstream commit 26e197b7f9240a4ac301dd0ad520c0c697c2ea7d ]

The blk_add_partition() function initially used a single if-condition
(IS_ERR(part)) to check for errors when adding a partition. This was
modified to handle the specific case of -ENXIO separately, allowing the
function to proceed without logging the error in this case. However,
this change unintentionally left a path where md_autodetect_dev()
could be called without confirming that part is a valid pointer.

This commit separates the error handling logic by splitting the
initial if-condition, improving code readability and handling specific
error scenarios explicitly. The function now distinguishes the general
error case from -ENXIO without altering the existing behavior of
md_autodetect_dev() calls.

Fixes: b72053072c0b (block: allow partitions on host aware zone devices)
Signed-off-by: Riyan Dhiman <riyandhiman14@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240911132954.5874-1-riyandhiman14@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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block: print symbolic error name instead of error code

[ Upstream commit 25c1772a0493463408489b1fae65cf77fe46cac1 ]

Utilize the %pe print specifier to get the symbolic error name as a
string (i.e "

block: print symbolic error name instead of error code

[ Upstream commit 25c1772a0493463408489b1fae65cf77fe46cac1 ]

Utilize the %pe print specifier to get the symbolic error name as a
string (i.e "-ENOMEM") in the log message instead of the error code to
increase its readablility.

This change was suggested in
https://lore.kernel.org/all/92972476-0b1f-4d0a-9951-af3fc8bc6e65@suswa.mountain/

Signed-off-by: Christian Heusel <christian@heusel.eu>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20240111231521.1596838-1-christian@heusel.eu
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Stable-dep-of: 26e197b7f924 ("block: fix potential invalid pointer dereference in blk_add_partition")
Signed-off-by: Sasha Levin <sashal@kernel.org>

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block: fix and simplify blkdevparts= cmdline parsing

[ Upstream commit bc2e07dfd2c49aaa4b52302cf7b55cf94e025f79 ]

Fix the cmdline parsing of the "blkdevparts=" parameter using strsep(),
which makes

block: fix and simplify blkdevparts= cmdline parsing

[ Upstream commit bc2e07dfd2c49aaa4b52302cf7b55cf94e025f79 ]

Fix the cmdline parsing of the "blkdevparts=" parameter using strsep(),
which makes the code simpler.

Before commit 146afeb235cc ("block: use strscpy() to instead of
strncpy()"), we used a strncpy() to copy a block device name and partition
names. The commit simply replaced a strncpy() and NULL termination with
a strscpy(). It did not update calculations of length passed to strscpy().
While the length passed to strncpy() is just a length of valid characters
without NULL termination ('\0'), strscpy() takes it as a length of the
destination buffer, including a NULL termination.

Since the source buffer is not necessarily NULL terminated, the current
code copies "length - 1" characters and puts a NULL character in the
destination buffer. It replaces the last character with NULL and breaks
the parsing.

As an example, that buffer will be passed to parse_parts() and breaks
parsing sub-partitions due to the missing ')' at the end, like the
following.

example (Check Point V-80 & OpenWrt):

- Linux Kernel 6.6

[ 0.000000] Kernel command line: console=ttyS0,115200 earlycon=uart8250,mmio32,0xf0512000 crashkernel=30M mvpp2x.queue_mode=1 blkdevparts=mmcblk1:48M@10M(kernel-1),1M(dtb-1),720M(rootfs-1),48M(kernel-2),1M(dtb-2),720M(rootfs-2),300M(default_sw),650M(logs),1M(preset_cfg),1M(adsl),-(storage) maxcpus=4
...
[ 0.884016] mmc1: new HS200 MMC card at address 0001
[ 0.889951] mmcblk1: mmc1:0001 004GA0 3.69 GiB
[ 0.895043] cmdline partition format is invalid.
[ 0.895704] mmcblk1: p1
[ 0.903447] mmcblk1boot0: mmc1:0001 004GA0 2.00 MiB
[ 0.908667] mmcblk1boot1: mmc1:0001 004GA0 2.00 MiB
[ 0.913765] mmcblk1rpmb: mmc1:0001 004GA0 512 KiB, chardev (248:0)

1. "48M@10M(kernel-1),..." is passed to strscpy() with length=17
from parse_parts()
2. strscpy() returns -E2BIG and the destination buffer has
"48M@10M(kernel-1\0"
3. "48M@10M(kernel-1\0" is passed to parse_subpart()
4. parse_subpart() fails to find ')' when parsing a partition name,
and returns error

- Linux Kernel 6.1

[ 0.000000] Kernel command line: console=ttyS0,115200 earlycon=uart8250,mmio32,0xf0512000 crashkernel=30M mvpp2x.queue_mode=1 blkdevparts=mmcblk1:48M@10M(kernel-1),1M(dtb-1),720M(rootfs-1),48M(kernel-2),1M(dtb-2),720M(rootfs-2),300M(default_sw),650M(logs),1M(preset_cfg),1M(adsl),-(storage) maxcpus=4
...
[ 0.953142] mmc1: new HS200 MMC card at address 0001
[ 0.959114] mmcblk1: mmc1:0001 004GA0 3.69 GiB
[ 0.964259] mmcblk1: p1(kernel-1) p2(dtb-1) p3(rootfs-1) p4(kernel-2) p5(dtb-2) 6(rootfs-2) p7(default_sw) p8(logs) p9(preset_cfg) p10(adsl) p11(storage)
[ 0.979174] mmcblk1boot0: mmc1:0001 004GA0 2.00 MiB
[ 0.984674] mmcblk1boot1: mmc1:0001 004GA0 2.00 MiB
[ 0.989926] mmcblk1rpmb: mmc1:0001 004GA0 512 KiB, chardev (248:0

By the way, strscpy() takes a length of destination buffer and it is
often confusing when copying characters with a specified length. Using
strsep() helps to separate the string by the specified character. Then,
we can use strscpy() naturally with the size of the destination buffer.

Separating the string on the fly is also useful to omit the redundant
string copy, reducing memory usage and improve the code readability.

Fixes: 146afeb235cc ("block: use strscpy() to instead of strncpy()")
Suggested-by: Naohiro Aota <naota@elisp.net>
Signed-off-by: INAGAKI Hiroshi <musashino.open@gmail.com>
Reviewed-by: Daniel Golle <daniel@makrotopia.org>
Link: https://lore.kernel.org/r/20240421074005.565-1-musashino.open@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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block: add a disk_has_partscan helper

commit 140ce28dd3bee8e53acc27f123ae474d69ef66f0 upstream.

Add a helper to check if partition scanning is enabled instead of
open coding the check in a few plac

block: add a disk_has_partscan helper

commit 140ce28dd3bee8e53acc27f123ae474d69ef66f0 upstream.

Add a helper to check if partition scanning is enabled instead of
open coding the check in a few places. This now always checks for
the hidden flag even if all but one of the callers are never reachable
for hidden gendisks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240502130033.1958492-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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