Bug 2264 - RekeyLimit option does not allow '4G' value when UINT_MAX is 0xffffffff
Summary: RekeyLimit option does not allow '4G' value when UINT_MAX is 0xffffffff
Status: CLOSED FIXED
Alias: None
Product: Portable OpenSSH
Classification: Unclassified
Component: sshd (show other bugs)
Version: 6.6p1
Hardware: Other Linux
: P5 normal
Assignee: Assigned to nobody
URL:
Keywords:
Depends on:
Blocks: V_7_2
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Reported: 2014-08-26 00:52 AEST by Garrett Lee
Modified: 2016-08-02 10:42 AEST (History)
2 users (show)

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Description Garrett Lee 2014-08-26 00:52:00 AEST 
When value '4G' is used to specify the RekeyLimit value, the configuration file parsing function, scan_scaled(), converts the 4G into value 4294967296 (in readconf.c and in servconf.c alike).

On systems where UINT_MAX is 0xffffffff, we are not able to configure value '4G' due to the 4294967296 being greater than 4294967295.  This appears to be a bug since one would expect a value of 4G to be able to be specified on a 32-bit OS.  The way in which the function set_newkeys() sets the value of max_blocks, it seems like openssh should be able to allow value 4G and perform the math to determine number of blocks before rekey takes place.
Comment 1 Damien Miller 2015-05-22 15:49:18 AEST 
rekey_limit is actually an int64_t, so this could probably be increased. That being said, 4G is a bit long between rekeys...
Comment 2 Damien Miller 2015-08-11 22:59:09 AEST 
Retarget pending bugs to openssh-7.1
Comment 3 Darren Tucker 2016-02-05 13:54:29 AEDT 
This has been fixed, you can now specify RekeyLimits up to 2**63.

https://anongit.mindrot.org/openssh.git/commit/?id=921ff00b0ac429666fb361d2d6cb1c8fff0006cb

upstream commit
Allow RekeyLimits in excess of 4G up to 2**63 bits
 (limited by the return type of scan_scaled).  Part of bz#2521, ok djm.

Upstream-ID: 13bea82be566b9704821b1ea05bf7804335c7979
Comment 4 Damien Miller 2016-08-02 10:42:00 AEST 
Close all resolved bugs after 7.3p1 release