Get new entropy on each attempt __gen_tempname (BZ #15813)

Message ID 20190725142550.18479-1-adhemerval.zanella@linaro.org
State Accepted
Commit e1df30fbc2e2167a982c0e77a7ebee28f4dd0800
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Series
  • Get new entropy on each attempt __gen_tempname (BZ #15813)
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Commit Message

Adhemerval Zanella July 25, 2019, 2:25 p.m.
This is missing bit for fully fix BZ#15813 (the other two were fixed
by 359653aaacad463).

Checked on x86_64-linux-gnu.

	[BZ #15813]
	sysdeps/posix/tempname.c (__gen_tempname): get entrypy on each
	attempt.
---
 sysdeps/posix/tempname.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

-- 
2.17.1

Comments

Florian Weimer July 29, 2019, 8:33 a.m. | #1
* Adhemerval Zanella:

> +  uint64_t pid = (uint64_t)__getpid () << 32;


Space after cast?  Rest of the change looks okay.

Thanks,
Florian
Adhemerval Zanella July 29, 2019, 5:55 p.m. | #2
On 29/07/2019 05:33, Florian Weimer wrote:
> * Adhemerval Zanella:

> 

>> +  uint64_t pid = (uint64_t)__getpid () << 32;

> 

> Space after cast?  Rest of the change looks okay.


Ack, changed locally.

> 

> Thanks,

> Florian

>
Carlos O'Donell July 29, 2019, 6:52 p.m. | #3
On 7/29/19 1:55 PM, Adhemerval Zanella wrote:
> 

> 

> On 29/07/2019 05:33, Florian Weimer wrote:

>> * Adhemerval Zanella:

>>

>>> +  uint64_t pid = (uint64_t)__getpid () << 32;

>>

>> Space after cast?  Rest of the change looks okay.

> 

> Ack, changed locally.


Are you OK with this waiting for 2.31 to open?

I'd like to minimize the changes to those we're making for
gcc 10 compatibility.

-- 
Cheers,
Carlos.
Adhemerval Zanella July 29, 2019, 6:59 p.m. | #4
On 29/07/2019 15:52, Carlos O'Donell wrote:
> On 7/29/19 1:55 PM, Adhemerval Zanella wrote:

>>

>>

>> On 29/07/2019 05:33, Florian Weimer wrote:

>>> * Adhemerval Zanella:

>>>

>>>> +  uint64_t pid = (uint64_t)__getpid () << 32;

>>>

>>> Space after cast?  Rest of the change looks okay.

>>

>> Ack, changed locally.

> 

> Are you OK with this waiting for 2.31 to open?

> 

> I'd like to minimize the changes to those we're making for

> gcc 10 compatibility.

> 


Certainly, I forgot to add on this fix that it is meant for 2.31.

Patch

diff --git a/sysdeps/posix/tempname.c b/sysdeps/posix/tempname.c
index de346949b2..e930211703 100644
--- a/sysdeps/posix/tempname.c
+++ b/sysdeps/posix/tempname.c
@@ -186,7 +186,6 @@  __gen_tempname (char *tmpl, int suffixlen, int flags, int kind)
 {
   int len;
   char *XXXXXX;
-  uint64_t value;
   unsigned int count;
   int fd = -1;
   int save_errno = errno;
@@ -218,13 +217,13 @@  __gen_tempname (char *tmpl, int suffixlen, int flags, int kind)
   /* This is where the Xs start.  */
   XXXXXX = &tmpl[len - 6 - suffixlen];
 
-  /* Get some more or less random data.  */
-  RANDOM_BITS (value);
-  value ^= (uint64_t)__getpid () << 32;
-
-  for (count = 0; count < attempts; value += 7777, ++count)
+  uint64_t pid = (uint64_t)__getpid () << 32;
+  for (count = 0; count < attempts; ++count)
     {
-      uint64_t v = value;
+      uint64_t v;
+      /* Get some more or less random data.  */
+      RANDOM_BITS (v);
+      v ^= pid;
 
       /* Fill in the random bits.  */
       XXXXXX[0] = letters[v % 62];