On 01/07/2013 10:46 AM, Neil Horman wrote:
On Mon, Jan 07, 2013 at 10:32:01AM -0500, Vlad Yasevich wrote:
On 01/07/2013 09:49 AM, Neil Horman wrote:
On Mon, Jan 07, 2013 at 02:25:39PM +0100, Florian Fainelli wrote:
Hello Neil,
Le 12/15/12 02:22, Neil Horman a écrit :
Recently I posted commit 3c68198e75 which made selection of the cookie hmac
algorithm selectable. This is all well and good, but Linus noted that it
changes the default config:
http://marc.info/?l=linux-netdev&m=135536629004808&w=2
I've modified the sctp Kconfig file to reflect the recommended way of making
this choice, using the thermal driver example specified, and brought the
defaults back into line with the way they were prior to my origional patch
Also, on Linus' suggestion, re-adding ability to select default 'none' hmac
algorithm, so we don't needlessly bloat the kernel by forcing a non-none
default. This also led me to note that we won't honor the default none
condition properly because of how sctp_net_init is encoded. Fix that up as
well.
Tested by myself (allbeit fairly quickly). All configuration combinations seems
to work soundly.
Signed-off-by: Neil Horman <nhorman@xxxxxxxxxxxxx>
CC: David Miller <davem@xxxxxxxxxxxxx>
CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
CC: Vlad Yasevich <vyasevich@xxxxxxxxx>
CC: linux-sctp@xxxxxxxxxxxxxxx
---
net/sctp/Kconfig | 27 +++++++++++++++++++++++++--
net/sctp/protocol.c | 4 ++--
2 files changed, 27 insertions(+), 4 deletions(-)
diff --git a/net/sctp/Kconfig b/net/sctp/Kconfig
index a9edd2e..c262106 100644
--- a/net/sctp/Kconfig
+++ b/net/sctp/Kconfig
@@ -66,12 +66,36 @@ config SCTP_DBG_OBJCNT
'cat /proc/net/sctp/sctp_dbg_objcnt'
If unsure, say N
+choice
+ prompt "Default SCTP cookie HMAC encoding"
+ default SCTP_COOKIE_HMAC_MD5
Should not this be SCTP_DEFAULT_COOKIE_HMAC_MD5? I just tried to
update to 3.8-rc2, and I usually build my kernel-headers with:
yes '' | ARCH=foo make oldconfig
and this just kept asking me for this config symbol because none
could be provided.
--
Florian
No, the config mechanism is setup to offer the user the ability to choose a
default cookie hmac, alg, then optionally select any other hmac algs you would
like to be made available (in the event you want to change the default at run
time). When you select the default, it eables (via the select directive), the
corresponding SCTP_COOKIE_HMAC_* config option, which is used in the build, and
then prompts for the remaining values.
Neil
Actually, I think it should be as Florian suggests. The default
value of the choice should be one of the values defined as part of
the choice (the SCTP_DEFAULT_COOKIE_*). Turning on appropriate
default would turn on appropriate cookie config
(SCTP_COOKIE_HMAC_*).
I absolutely disagree.
Would that save all the config trouble?
Yes, it would fix it as Florian has noted, but at the cost of silently modifying
what the default hmac config vaule is. If you've expressly disabled
SCTP_COOKIE_HMAC_MD5, and then blindly take the default choice in the
SCTP_DEFAULT_COOKIE selection option (the default default as it were), using the
approach your suggesting, then that will silently enable SCTP_COOKIE_HMAC_MD5
again, which may not be expected by users. If you expressly have a config
option disabled in an old configuration, we should leave it there.
GACK. Just reproduced this and I really don't like this infinite loop
of choice prompts. That's a horrible bug and we need to fix this.
I don't think overriding the value is that big of a deal, especially
considering that this is exactly what 'make menuconfig' and other
graphical configs will do.
If I start with:
CONFIG_IP_SCTP=m
CONFIG_NET_SCTPPROBE=m
# CONFIG_SCTP_DBG_MSG is not set
# CONFIG_SCTP_DBG_OBJCNT is not set
# CONFIG_SCTP_HMAC_NONE is not set
CONFIG_SCTP_HMAC_SHA1=y
# CONFIG_SCTP_HMAC_MD5 is not set
then run:
yes "" | make oldconfig
I get an infinite loop.
If I run "make menuconfig", I get:
CONFIG_IP_SCTP=m
CONFIG_NET_SCTPPROBE=m
# CONFIG_SCTP_DBG_MSG is not set
# CONFIG_SCTP_DBG_OBJCNT is not set
CONFIG_SCTP_DEFAULT_COOKIE_HMAC_MD5=y
# CONFIG_SCTP_DEFAULT_COOKIE_HMAC_SHA1 is not set
# CONFIG_SCTP_DEFAULT_COOKIE_HMAC_NONE is not set
CONFIG_SCTP_COOKIE_HMAC_MD5=y
# CONFIG_SCTP_COOKIE_HMAC_SHA1 is not set
Note, that SHA1 is now overridden with MD5.
If I change the value of the default choice in Kconfig, the behavior
between oldconfig and menuconfig is the same.
-vlad
We're doing the right thing now, IMO. When presented with a conflictly set
of configuration options, the config utilty is (repeatedly) prompting us to
resolve them. That seems like a much more reasonable approach to this, than
silently changing pre-existing options so people can do the equivalent of just
blindly pressing enter through the config process (which is all yes "" | make
oldconfig is).
This is a momentary hiccup, corrected by taking 30 seconds to make a manual
config change (or by taking a second to understand what the config utility is
tell us by prompting for a default choice repeatedly). Theres nothing to fix
here.
Neil
-vlad
Neil
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