Re: [OE-core] [kirkstone][PATCH] u-boot: fix CVE-2022-33103

* Re: [OE-core] [kirkstone][PATCH] u-boot: fix CVE-2022-33103
       [not found] <1705773DE10A5E2A.21236@lists.openembedded.org>
@ 2022-08-10 15:34 ` Sakib Sajal
  2022-08-10 16:30   ` Steve Sakoman
  0 siblings, 1 reply; 3+ messages in thread
From: Sakib Sajal @ 2022-08-10 15:34 UTC (permalink / raw)
  To: openembedded-core; +Cc: Steve Sakoman

Steve, did you miss this patch?

On 2022-07-26 15:18, Sakib Sajal wrote:
> Backport patch to resolve CVE-2022-33103.
>
> Signed-off-by: Sakib Sajal <sakib.sajal@windriver.com>
> ---
>   ..._read-Prevent-arbitrary-code-executi.patch | 80 +++++++++++++++++++
>   meta/recipes-bsp/u-boot/u-boot_2022.01.bb     |  1 +
>   2 files changed, 81 insertions(+)
>   create mode 100644 meta/recipes-bsp/u-boot/files/0001-fs-squashfs-sqfs_read-Prevent-arbitrary-code-executi.patch
>
> diff --git a/meta/recipes-bsp/u-boot/files/0001-fs-squashfs-sqfs_read-Prevent-arbitrary-code-executi.patch b/meta/recipes-bsp/u-boot/files/0001-fs-squashfs-sqfs_read-Prevent-arbitrary-code-executi.patch
> new file mode 100644
> index 0000000000..b1650f6baa
> --- /dev/null
> +++ b/meta/recipes-bsp/u-boot/files/0001-fs-squashfs-sqfs_read-Prevent-arbitrary-code-executi.patch
> @@ -0,0 +1,80 @@
> +From 65f1066f5abe291c7b10b6075fd60776074a38a9 Mon Sep 17 00:00:00 2001
> +From: Miquel Raynal <miquel.raynal@bootlin.com>
> +Date: Thu, 9 Jun 2022 16:02:06 +0200
> +Subject: [PATCH] fs/squashfs: sqfs_read: Prevent arbitrary code execution
> +
> +Following Jincheng's report, an out-of-band write leading to arbitrary
> +code execution is possible because on one side the squashfs logic
> +accepts directory names up to 65535 bytes (u16), while U-Boot fs logic
> +accepts directory names up to 255 bytes long.
> +
> +Prevent such an exploit from happening by capping directory name sizes
> +to 255. Use a define for this purpose so that developers can link the
> +limitation to its source and eventually kill it some day by dynamically
> +allocating this array (if ever desired).
> +
> +Link: https://lore.kernel.org/all/CALO=DHFB+yBoXxVr5KcsK0iFdg+e7ywko4-e+72kjbcS8JBfPw@mail.gmail.com
> +Reported-by: Jincheng Wang <jc.w4ng@gmail.com>
> +Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> +Tested-by: Jincheng Wang <jc.w4ng@gmail.com>
> +
> +CVE: CVE-2022-33103
> +Upstream-Status: Backport [2ac0baab4aff1a0b45067d0b62f00c15f4e86856]
> +
> +Signed-off-by: Sakib Sajal <sakib.sajal@windriver.com>
> +---
> + fs/squashfs/sqfs.c | 8 +++++---
> + include/fs.h       | 4 +++-
> + 2 files changed, 8 insertions(+), 4 deletions(-)
> +
> +diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
> +index e2d91c654c..a145d754cc 100644
> +--- a/fs/squashfs/sqfs.c
> ++++ b/fs/squashfs/sqfs.c
> +@@ -973,6 +973,7 @@ int sqfs_readdir(struct fs_dir_stream *fs_dirs, struct fs_dirent **dentp)
> + 	int i_number, offset = 0, ret;
> + 	struct fs_dirent *dent;
> + 	unsigned char *ipos;
> ++	u16 name_size;
> +
> + 	dirs = (struct squashfs_dir_stream *)fs_dirs;
> + 	if (!dirs->size) {
> +@@ -1055,9 +1056,10 @@ int sqfs_readdir(struct fs_dir_stream *fs_dirs, struct fs_dirent **dentp)
> + 		return -SQFS_STOP_READDIR;
> + 	}
> +
> +-	/* Set entry name */
> +-	strncpy(dent->name, dirs->entry->name, dirs->entry->name_size + 1);
> +-	dent->name[dirs->entry->name_size + 1] = '\0';
> ++	/* Set entry name (capped at FS_DIRENT_NAME_LEN which is a U-Boot limitation) */
> ++	name_size = min_t(u16, dirs->entry->name_size + 1, FS_DIRENT_NAME_LEN - 1);
> ++	strncpy(dent->name, dirs->entry->name, name_size);
> ++	dent->name[name_size] = '\0';
> +
> + 	offset = dirs->entry->name_size + 1 + SQFS_ENTRY_BASE_LENGTH;
> + 	dirs->entry_count--;
> +diff --git a/include/fs.h b/include/fs.h
> +index 1c79e299fd..6cb7ec89f4 100644
> +--- a/include/fs.h
> ++++ b/include/fs.h
> +@@ -161,6 +161,8 @@ int fs_write(const char *filename, ulong addr, loff_t offset, loff_t len,
> + #define FS_DT_REG  8         /* regular file */
> + #define FS_DT_LNK  10        /* symbolic link */
> +
> ++#define FS_DIRENT_NAME_LEN 256
> ++
> + /**
> +  * struct fs_dirent - directory entry
> +  *
> +@@ -181,7 +183,7 @@ struct fs_dirent {
> + 	/** change_time:	time of last modification */
> + 	struct rtc_time change_time;
> + 	/** name:		file name */
> +-	char name[256];
> ++	char name[FS_DIRENT_NAME_LEN];
> + };
> +
> + /* Note: fs_dir_stream should be treated as opaque to the user of fs layer */
> +--
> +2.33.0
> +
> diff --git a/meta/recipes-bsp/u-boot/u-boot_2022.01.bb b/meta/recipes-bsp/u-boot/u-boot_2022.01.bb
> index f2443723e2..a6a15d698f 100644
> --- a/meta/recipes-bsp/u-boot/u-boot_2022.01.bb
> +++ b/meta/recipes-bsp/u-boot/u-boot_2022.01.bb
> @@ -4,6 +4,7 @@ require u-boot.inc
>   SRC_URI:append = " file://0001-riscv32-Use-double-float-ABI-for-rv32.patch \
>                      file://0001-riscv-fix-build-with-binutils-2.38.patch \
>                      file://0001-i2c-fix-stack-buffer-overflow-vulnerability-in-i2c-m.patch \
> +                   file://0001-fs-squashfs-sqfs_read-Prevent-arbitrary-code-executi.patch \
>                    "
>   
>   DEPENDS += "bc-native dtc-native python3-setuptools-native"
>
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