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Linux kernel source tree
707823e7f2
KASAN reported the following issue: [ 36.825817][ T5923] BUG: KASAN: wild-memory-access in v9fs_get_acl+0x1a4/0x390 [ 36.827479][ T5923] Write of size 4 at addr 9fffeb37f97f1c00 by task syz-executor798/5923 [ 36.829303][ T5923] [ 36.829846][ T5923] CPU: 0 PID: 5923 Comm: syz-executor798 Not tainted 6.2.0-syzkaller-18302-g596b6b709632 #0 [ 36.832110][ T5923] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023 [ 36.834464][ T5923] Call trace: [ 36.835196][ T5923] dump_backtrace+0x1c8/0x1f4 [ 36.836229][ T5923] show_stack+0x2c/0x3c [ 36.837100][ T5923] dump_stack_lvl+0xd0/0x124 [ 36.838103][ T5923] print_report+0xe4/0x4c0 [ 36.839068][ T5923] kasan_report+0xd4/0x130 [ 36.840052][ T5923] kasan_check_range+0x264/0x2a4 [ 36.841199][ T5923] __kasan_check_write+0x2c/0x3c [ 36.842216][ T5923] v9fs_get_acl+0x1a4/0x390 [ 36.843232][ T5923] v9fs_mount+0x77c/0xa5c [ 36.844163][ T5923] legacy_get_tree+0xd4/0x16c [ 36.845173][ T5923] vfs_get_tree+0x90/0x274 [ 36.846137][ T5923] do_new_mount+0x25c/0x8c8 [ 36.847066][ T5923] path_mount+0x590/0xe58 [ 36.848147][ T5923] __arm64_sys_mount+0x45c/0x594 [ 36.849273][ T5923] invoke_syscall+0x98/0x2c0 [ 36.850421][ T5923] el0_svc_common+0x138/0x258 [ 36.851397][ T5923] do_el0_svc+0x64/0x198 [ 36.852398][ T5923] el0_svc+0x58/0x168 [ 36.853224][ T5923] el0t_64_sync_handler+0x84/0xf0 [ 36.854293][ T5923] el0t_64_sync+0x190/0x194 Calling '__v9fs_get_acl' method in 'v9fs_get_acl' creates the following chain of function calls: __v9fs_get_acl v9fs_fid_get_acl v9fs_fid_xattr_get p9_client_xattrwalk Function p9_client_xattrwalk accepts a pointer to u64-typed variable attr_size and puts some u64 value into it. However, after the executing the p9_client_xattrwalk, in some circumstances we assign the value of u64-typed variable 'attr_size' to the variable 'retval', which we will return. However, the type of 'retval' is ssize_t, and if the value of attr_size is larger than SSIZE_MAX, we will face the signed type overflow. If the overflow occurs, the result of v9fs_fid_xattr_get may be negative, but not classified as an error. When we try to allocate an acl with 'broken' size we receive an error, but don't process it. When we try to free this acl, we face the 'wild-memory-access' error (because it wasn't allocated). This patch will add new condition to the 'v9fs_fid_xattr_get' function, so it will return an EOVERFLOW error if the 'attr_size' is larger than SSIZE_MAX. In this version of the patch I simplified the condition. In previous (v2) version of the patch I removed explicit type conversion and added separate condition to check the possible overflow and return an error (in v1 version I've just modified the existing condition). Tested via syzkaller. Suggested-by: Christian Schoenebeck <linux_oss@crudebyte.com> Reported-by: syzbot+cb1d16facb3cc90de5fb@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=fbbef66d9e4d096242f3617de5d14d12705b4659 Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com> Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org> |
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Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.