| Message ID | 20170711134709.29343-1-chandan@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/fs/filesystems.c b/fs/filesystems.c index a920ad2..8e309d3 100644 --- a/fs/filesystems.c +++ b/fs/filesystems.c @@ -275,6 +275,9 @@ struct file_system_type *get_fs_type(const char *name) const char *dot = strchr(name, '.'); int len = dot ? dot - name : strlen(name); + if (len >= PATH_MAX) + return NULL; + fs = __get_fs_type(name, len); if (!fs && (request_module("fs-%.*s", len, name) == 0)) { fs = __get_fs_type(name, len);
On ppc64, When a non-nul terminated string is passed as an argument to the mount(2) syscall, copy_mount_string() ends up allocating 64k (the PAGE_SIZE on ppc64) worth of space for holding the string in kernel's address space. Later, in set_precision() (invoked indirectly by get_fs_type()), we end up assigning 65535 as the value to 'struct printf_spec'->precision member. This field has a width of 16 bits and hence a truncated version of the original value ends up being assigned. This causes the "WARN_ONCE(spec->precision != prec, "precision %d too large", prec)" statement inside set_precision() to be executed. This commit fixes the bug by validating the length of the "filesystem type" argument passed to get_fs_type() function. Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com> Suggested-by: Joe Perches <joe@perches.com> --- fs/filesystems.c | 3 +++ 1 file changed, 3 insertions(+)