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* [glibc] malloc: Assure that THP mode is always null terminated
@ 2023-04-13 20:18 Adhemerval Zanella
  2023-04-14  6:52 ` Andreas Schwab
  0 siblings, 1 reply; 3+ messages in thread
From: Adhemerval Zanella @ 2023-04-13 20:18 UTC (permalink / raw)
  To: glibc-cvs

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=801deb07f6ecc6a3c8933cffc23d4b3a895259e1

commit 801deb07f6ecc6a3c8933cffc23d4b3a895259e1
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Wed Apr 12 09:36:54 2023 -0300

    malloc: Assure that THP mode is always null terminated

Diff:
---
 sysdeps/unix/sysv/linux/malloc-hugepages.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/sysdeps/unix/sysv/linux/malloc-hugepages.c b/sysdeps/unix/sysv/linux/malloc-hugepages.c
index 683d68c327..740027ebfb 100644
--- a/sysdeps/unix/sysv/linux/malloc-hugepages.c
+++ b/sysdeps/unix/sysv/linux/malloc-hugepages.c
@@ -61,6 +61,7 @@ __malloc_thp_mode (void)
 
   char str[sizeof(mode_always)];
   ssize_t s = __read_nocancel (fd, str, sizeof (str));
+  str[s] = '\0';
   __close_nocancel (fd);
 
   if (s == sizeof (mode_always) - 1)

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [glibc] malloc: Assure that THP mode is always null terminated
  2023-04-13 20:18 [glibc] malloc: Assure that THP mode is always null terminated Adhemerval Zanella
@ 2023-04-14  6:52 ` Andreas Schwab
  2023-04-14 11:02   ` Adhemerval Zanella
  0 siblings, 1 reply; 3+ messages in thread
From: Andreas Schwab @ 2023-04-14  6:52 UTC (permalink / raw)
  To: Adhemerval Zanella via Glibc-cvs; +Cc: Adhemerval Zanella

On Apr 13 2023, Adhemerval Zanella via Glibc-cvs wrote:

> diff --git a/sysdeps/unix/sysv/linux/malloc-hugepages.c b/sysdeps/unix/sysv/linux/malloc-hugepages.c
> index 683d68c327..740027ebfb 100644
> --- a/sysdeps/unix/sysv/linux/malloc-hugepages.c
> +++ b/sysdeps/unix/sysv/linux/malloc-hugepages.c
> @@ -61,6 +61,7 @@ __malloc_thp_mode (void)
>  
>    char str[sizeof(mode_always)];
>    ssize_t s = __read_nocancel (fd, str, sizeof (str));
> +  str[s] = '\0';

This is a buffer overflow if s >= sizeof (str) or s < 0.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [glibc] malloc: Assure that THP mode is always null terminated
  2023-04-14  6:52 ` Andreas Schwab
@ 2023-04-14 11:02   ` Adhemerval Zanella
  0 siblings, 0 replies; 3+ messages in thread
From: Adhemerval Zanella @ 2023-04-14 11:02 UTC (permalink / raw)
  To: Andreas Schwab; +Cc: Adhemerval Zanella via Glibc-cvs, Adhemerval Zanella



> On 14 Apr 2023, at 03:52, Andreas Schwab <schwab@linux-m68k.org> wrote:
> 
> On Apr 13 2023, Adhemerval Zanella via Glibc-cvs wrote:
> 
>> diff --git a/sysdeps/unix/sysv/linux/malloc-hugepages.c b/sysdeps/unix/sysv/linux/malloc-hugepages.c
>> index 683d68c327..740027ebfb 100644
>> --- a/sysdeps/unix/sysv/linux/malloc-hugepages.c
>> +++ b/sysdeps/unix/sysv/linux/malloc-hugepages.c
>> @@ -61,6 +61,7 @@ __malloc_thp_mode (void)
>> 
>>   char str[sizeof(mode_always)];
>>   ssize_t s = __read_nocancel (fd, str, sizeof (str));
>> +  str[s] = '\0';
> 
> This is a buffer overflow if s >= sizeof (str) or s < 0.

Indeed, thanks for catching it. I will fix it.

^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-04-14 11:02 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2023-04-13 20:18 [glibc] malloc: Assure that THP mode is always null terminated Adhemerval Zanella
2023-04-14  6:52 ` Andreas Schwab
2023-04-14 11:02   ` Adhemerval Zanella

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