From: "Yann Droneaud" <ydroneaud@opteya.com>
To: "Adhemerval Zanella" <adhemerval.zanella@linaro.org>,
libc-alpha@sourceware.org
Subject: Re: [PATCH v2] malloc: Do not clobber errno on __getrandom_nocancel (BZ#29624)
Date: Thu, 29 Sep 2022 18:44:25 +0000 [thread overview]
Message-ID: <fc1cb3ee16572e5eeba3a1534e21bbc8408609e4@opteya.com> (raw)
In-Reply-To: <20220929175526.2596756-1-adhemerval.zanella@linaro.org>
Hi,
29 septembre 2022 à 19:56 "Adhemerval Zanella via Libc-alpha" a écrit:
>
> Use INTERNAL_SYSCALL_CALL instead of INLINE_SYSCALL_CALL. This
> requires emulate the semantic for hurd call (so __arc4random_buf
> uses the fallback).
>
> Checked on x86_64-linux-gnu.
> ---
> stdlib/arc4random.c | 4 ++--
> sysdeps/mach/hurd/not-cancel.h | 12 ++++++++++--
> sysdeps/unix/sysv/linux/not-cancel.h | 2 +-
> 3 files changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/stdlib/arc4random.c b/stdlib/arc4random.c
> index e417ef624d..0a1f4b8a57 100644
> --- a/stdlib/arc4random.c
> +++ b/stdlib/arc4random.c
> @@ -34,7 +34,7 @@ void
> __arc4random_buf (void *p, size_t n)
> {
> static int seen_initialized;
> - size_t l;
> + int l;
> int fd;
>
> if (n == 0)
> @@ -51,7 +51,7 @@ __arc4random_buf (void *p, size_t n)
> n -= l;
> continue; /* Interrupted by a signal; keep going. */
> }
> - else if (l < 0 && errno == ENOSYS)
Aside: I failed to noticed this (the fact is, except commit message, I didn't review much Jason's patch) .
https://sourceware.org/pipermail/libc-alpha/2022-July/141049.html
l being size_t, it cannot be less than 0, thus is there a chance it can actually fallback to reading /dev/urandom ?
> + else if (l == -ENOSYS)
> break; /* No syscall, so fallback to /dev/urandom. */
> arc4random_getrandom_failure ();
> }
> diff --git a/sysdeps/mach/hurd/not-cancel.h b/sysdeps/mach/hurd/not-cancel.h
> index ae58b734e3..518f738519 100644
> --- a/sysdeps/mach/hurd/not-cancel.h
> +++ b/sysdeps/mach/hurd/not-cancel.h
> @@ -27,6 +27,7 @@
> #include <sys/uio.h>
> #include <hurd.h>
> #include <hurd/fd.h>
> +#include <sys/random.h>
>
> /* Non cancellable close syscall. */
> __typeof (__close) __close_nocancel;
> @@ -75,8 +76,15 @@ __typeof (__fcntl) __fcntl_nocancel;
> #define __fcntl64_nocancel(...) \
> __fcntl_nocancel (__VA_ARGS__)
>
> -#define __getrandom_nocancel(buf, size, flags) \
> - __getrandom (buf, size, flags)
> +static inline int
> +__getrandom_nocancel (void *buf, size_t buflen, unsigned int flags)
> +{
> + int save_errno = errno;
> + int r = __getrandom (buf, buflen, flags);
> + r = r == -1 ? -errno : r;
> + __set_errno (save_errno);
> + return r;
> +}
>
> #define __poll_infinity_nocancel(fds, nfds) \
> __poll (fds, nfds, -1)
> diff --git a/sysdeps/unix/sysv/linux/not-cancel.h b/sysdeps/unix/sysv/linux/not-cancel.h
> index a263d294b1..00ab75a405 100644
> --- a/sysdeps/unix/sysv/linux/not-cancel.h
> +++ b/sysdeps/unix/sysv/linux/not-cancel.h
> @@ -71,7 +71,7 @@ __writev_nocancel_nostatus (int fd, const struct iovec *iov, int iovcnt)
> static inline int
> __getrandom_nocancel (void *buf, size_t buflen, unsigned int flags)
> {
> - return INLINE_SYSCALL_CALL (getrandom, buf, buflen, flags);
> + return INTERNAL_SYSCALL_CALL (getrandom, buf, buflen, flags);
> }
>
> static inline int
> --
> 2.34.1
>
Reviewed-by: Yann Droneaud <ydroneaud@opteya.com>
--
Yann Droneaud
OPTEYA
prev parent reply other threads:[~2022-09-29 18:44 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-29 17:55 Adhemerval Zanella
2022-09-29 18:36 ` Wilco Dijkstra
2022-09-29 19:07 ` Adhemerval Zanella Netto
2022-09-29 19:36 ` H.J. Lu
2022-09-29 18:44 ` Yann Droneaud [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=fc1cb3ee16572e5eeba3a1534e21bbc8408609e4@opteya.com \
--to=ydroneaud@opteya.com \
--cc=adhemerval.zanella@linaro.org \
--cc=libc-alpha@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).