[v3,0/4] Make sscanf() stricter

Message

Demi Marie Obenour June 10, 2023, 8:40 p.m. UTC

Roger Pau Monné suggested making xenbus_scanf() stricter instead of
using a custom parser.  Christoph Hellwig asked why the normal vsscanf()
cannot be made stricter.  Richard Weinberger mentioned Linus Torvalds’s
suggestion of using ! to allow overflow.

Changes since v2:

- Better commit messages.
- Fix a compile error in simple_strtoll() (found by 0day bot).
- Fix an uninitialized variable (found by Dan Carpenter).

Changes since v1:

- Better commit messages.
- Use ! to explicitly opt-in to allowing overflow.
- Treat overflow as a conversion failure instead of returning ERANGE.
- Drop the first patch (removal of simple_strtoll()) as it breaks
  bcache.
- Stop skipping spaces in vsscanf() instead of adding a separate
  vsscanf_strict() function.

Demi Marie Obenour (4):
  limits.h: add UCHAR_MAX, SCHAR_MAX, and SCHAR_MIN
  vsscanf(): Integer overflow is a conversion failure
  vsscanf(): do not skip spaces
  Reject NUL bytes in xenstore nodes

 .../hive_isp_css_include/platform_support.h   |  1 -
 drivers/xen/xenbus/xenbus_xs.c                | 17 +++-
 include/linux/limits.h                        |  1 +
 include/linux/mfd/wl1273-core.h               |  3 -
 include/vdso/limits.h                         |  3 +
 lib/vsprintf.c                                | 98 +++++++++++++------
 6 files changed, 86 insertions(+), 37 deletions(-)

Comments

Andy Shevchenko June 12, 2023, 3:34 p.m. UTC | #1

On Sat, Jun 10, 2023 at 04:40:40PM -0400, Demi Marie Obenour wrote:
> Roger Pau Monné suggested making xenbus_scanf() stricter instead of
> using a custom parser.  Christoph Hellwig asked why the normal vsscanf()
> cannot be made stricter.  Richard Weinberger mentioned Linus Torvalds’s
> suggestion of using ! to allow overflow.

As Rasmus articulated, NAK w.o. test cases being added to all parts where your
changes touch.