| Message ID | 20240525121341.3154251-1-hjl.tools@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | parse_fdinfo: Don't advance pointer twice [BZ #31798] | expand |
On 25/05/24 09:13, H.J. Lu wrote: > pidfd_getpid.c has > > /* Ignore invalid large values. */ > if (INT_MULTIPLY_WRAPV (10, n, &n) > || INT_ADD_WRAPV (n, *l++ - '0', &n)) > return -1; > > For GCC older than GCC 7, INT_ADD_WRAPV(a, b, r) is defined as > > _GL_INT_OP_WRAPV (a, b, r, +, _GL_INT_ADD_RANGE_OVERFLOW) > > and *l++ - '0' is evaluated twice. Fix BZ #31798 by moving "l++" out of > the if statement. Tested with GCC 6.4 and GCC 14.1. > > Signed-off-by: H.J. Lu <hjl.tools@gmail.com> The intprops.h is clear about it: 341 These macros may evaluate their arguments zero or multiple times, so the 342 arguments should not have side effects. LGTM, thanks. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > --- > sysdeps/unix/sysv/linux/pidfd_getpid.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/sysdeps/unix/sysv/linux/pidfd_getpid.c b/sysdeps/unix/sysv/linux/pidfd_getpid.c > index ebcbe8fdf6..6967477fab 100644 > --- a/sysdeps/unix/sysv/linux/pidfd_getpid.c > +++ b/sysdeps/unix/sysv/linux/pidfd_getpid.c > @@ -74,8 +74,10 @@ parse_fdinfo (const char *l, void *arg) > > /* Ignore invalid large values. */ > if (INT_MULTIPLY_WRAPV (10, n, &n) > - || INT_ADD_WRAPV (n, *l++ - '0', &n)) > + || INT_ADD_WRAPV (n, *l - '0', &n)) > return -1; > + > + l++; > } > > /* -1 indicates that the process is terminated. */
diff --git a/sysdeps/unix/sysv/linux/pidfd_getpid.c b/sysdeps/unix/sysv/linux/pidfd_getpid.c index ebcbe8fdf6..6967477fab 100644 --- a/sysdeps/unix/sysv/linux/pidfd_getpid.c +++ b/sysdeps/unix/sysv/linux/pidfd_getpid.c @@ -74,8 +74,10 @@ parse_fdinfo (const char *l, void *arg) /* Ignore invalid large values. */ if (INT_MULTIPLY_WRAPV (10, n, &n) - || INT_ADD_WRAPV (n, *l++ - '0', &n)) + || INT_ADD_WRAPV (n, *l - '0', &n)) return -1; + + l++; } /* -1 indicates that the process is terminated. */
pidfd_getpid.c has /* Ignore invalid large values. */ if (INT_MULTIPLY_WRAPV (10, n, &n) || INT_ADD_WRAPV (n, *l++ - '0', &n)) return -1; For GCC older than GCC 7, INT_ADD_WRAPV(a, b, r) is defined as _GL_INT_OP_WRAPV (a, b, r, +, _GL_INT_ADD_RANGE_OVERFLOW) and *l++ - '0' is evaluated twice. Fix BZ #31798 by moving "l++" out of the if statement. Tested with GCC 6.4 and GCC 14.1. Signed-off-by: H.J. Lu <hjl.tools@gmail.com> --- sysdeps/unix/sysv/linux/pidfd_getpid.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)