| Message ID | 20200131020823.29824-1-ce3g8jdj@umail.furryterror.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | inspect: make sure LOGICAL_INO_V2 args are zero-initialized | expand |
On 2020/1/31 上午10:08, Zygo Blaxell wrote: > LOGICAL_INO v1 ignored the reserved fields, so they could be filled > with random stack garbage and have no effect. LOGICAL_INO_V2 requires > all unused reserved bits to be set to zero, and returns EINVAL if they > are not, to guard against future kernel versions which may interpret > non-zero bit values. > > Sometimes when 'btrfs ins log' runs, the stack garbage is zeros, so the > -o (ignore offsets) option for logical-resolve works. Sometimes the > stack garbage is something else, and 'btrfs ins log -o' fails with > invalid argument. This depends mostly on compiler version and build > environment details, so a binary typically either always works or never > works. > > Fix by initializing logical-resolve's argument structure with a C99 > compound literal zero. > > Signed-off-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org> Reviewed-by: Qu Wenruo <wqu@suse.com> Thanks, Qu > --- > cmds/inspect.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/cmds/inspect.c b/cmds/inspect.c > index 9ca78611..5b946da0 100644 > --- a/cmds/inspect.c > +++ b/cmds/inspect.c > @@ -149,7 +149,7 @@ static int cmd_inspect_logical_resolve(const struct cmd_struct *cmd, > int verbose = 0; > int getpath = 1; > int bytes_left; > - struct btrfs_ioctl_logical_ino_args loi; > + struct btrfs_ioctl_logical_ino_args loi = { 0 }; > struct btrfs_data_container *inodes; > u64 size = SZ_64K; > char full_path[PATH_MAX]; >
On Thu, Jan 30, 2020 at 09:08:23PM -0500, Zygo Blaxell wrote: > LOGICAL_INO v1 ignored the reserved fields, so they could be filled > with random stack garbage and have no effect. LOGICAL_INO_V2 requires > all unused reserved bits to be set to zero, and returns EINVAL if they > are not, to guard against future kernel versions which may interpret > non-zero bit values. > > Sometimes when 'btrfs ins log' runs, the stack garbage is zeros, so the > -o (ignore offsets) option for logical-resolve works. Sometimes the > stack garbage is something else, and 'btrfs ins log -o' fails with > invalid argument. This depends mostly on compiler version and build > environment details, so a binary typically either always works or never > works. > > Fix by initializing logical-resolve's argument structure with a C99 > compound literal zero. > > Signed-off-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org> Added to devel, thanks.
diff --git a/cmds/inspect.c b/cmds/inspect.c index 9ca78611..5b946da0 100644 --- a/cmds/inspect.c +++ b/cmds/inspect.c @@ -149,7 +149,7 @@ static int cmd_inspect_logical_resolve(const struct cmd_struct *cmd, int verbose = 0; int getpath = 1; int bytes_left; - struct btrfs_ioctl_logical_ino_args loi; + struct btrfs_ioctl_logical_ino_args loi = { 0 }; struct btrfs_data_container *inodes; u64 size = SZ_64K; char full_path[PATH_MAX];
LOGICAL_INO v1 ignored the reserved fields, so they could be filled with random stack garbage and have no effect. LOGICAL_INO_V2 requires all unused reserved bits to be set to zero, and returns EINVAL if they are not, to guard against future kernel versions which may interpret non-zero bit values. Sometimes when 'btrfs ins log' runs, the stack garbage is zeros, so the -o (ignore offsets) option for logical-resolve works. Sometimes the stack garbage is something else, and 'btrfs ins log -o' fails with invalid argument. This depends mostly on compiler version and build environment details, so a binary typically either always works or never works. Fix by initializing logical-resolve's argument structure with a C99 compound literal zero. Signed-off-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org> --- cmds/inspect.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)