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path: root/fs/cifs/dns_resolve.c
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2010-08-05DNS: Separate out CIFS DNS Resolver codeWang Lei
Separate out the DNS resolver key type from the CIFS filesystem into its own module so that it can be made available for general use, including the AFS filesystem module. This facility makes it possible for the kernel to upcall to userspace to have it issue DNS requests, package up the replies and present them to the kernel in a useful form. The kernel is then able to cache the DNS replies as keys can be retained in keyrings. Resolver keys are of type "dns_resolver" and have a case-insensitive description that is of the form "[<type>:]<domain_name>". The optional <type> indicates the particular DNS lookup and packaging that's required. The <domain_name> is the query to be made. If <type> isn't given, a basic hostname to IP address lookup is made, and the result is stored in the key in the form of a printable string consisting of a comma-separated list of IPv4 and IPv6 addresses. This key type is supported by userspace helpers driven from /sbin/request-key and configured through /etc/request-key.conf. The cifs.upcall utility is invoked for UNC path server name to IP address resolution. The CIFS functionality is encapsulated by the dns_resolve_unc_to_ip() function, which is used to resolve a UNC path to an IP address for CIFS filesystem. This part remains in the CIFS module for now. See the added Documentation/networking/dns_resolver.txt for more information. Signed-off-by: Wang Lei <wang840925@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-05CIFS: Make cifs_convert_address() take a const src pointer and a lengthDavid Howells
Make cifs_convert_address() take a const src pointer and a length so that all the strlen() calls in their can be cut out and to make it unnecessary to modify the src string. Also return the data length from dns_resolve_server_name_to_ip() so that a strlen() can be cut out of cifs_compose_mount_options() too. Acked-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02cifs: set the port in sockaddr in a more clearly defined fashionJeff Layton
This patch should replace the patch I sent a couple of weeks ago to set the port in cifs_convert_address. Currently we set this in cifs_find_tcp_session, but that's more of a side effect than anything. Add a new function called cifs_fill_sockaddr. Have it call cifs_convert_address and then set the port. This also allows us to skip passing in the port as a separate parm to cifs_find_tcp_session. Also, change cifs_convert_address take a struct sockaddr * rather than void * to make it clearer how this function should be called. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-07-30CIFS: Remove __exit mark from cifs_exit_dns_resolver()David Howells
Remove the __exit mark from cifs_exit_dns_resolver() as it's called by the module init routine in case of error, and so may have been discarded during linkage. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-07-22CIFS: Fix a malicious redirect problem in the DNS lookup codeDavid Howells
Fix the security problem in the CIFS filesystem DNS lookup code in which a malicious redirect could be installed by a random user by simply adding a result record into one of their keyrings with add_key() and then invoking a CIFS CFS lookup [CVE-2010-2524]. This is done by creating an internal keyring specifically for the caching of DNS lookups. To enforce the use of this keyring, the module init routine creates a set of override credentials with the keyring installed as the thread keyring and instructs request_key() to only install lookup result keys in that keyring. The override is then applied around the call to request_key(). This has some additional benefits when a kernel service uses this module to request a key: (1) The result keys are owned by root, not the user that caused the lookup. (2) The result keys don't pop up in the user's keyrings. (3) The result keys don't come out of the quota of the user that caused the lookup. The keyring can be viewed as root by doing cat /proc/keys: 2a0ca6c3 I----- 1 perm 1f030000 0 0 keyring .dns_resolver: 1/4 It can then be listed with 'keyctl list' by root. # keyctl list 0x2a0ca6c3 1 key in keyring: 726766307: --alswrv 0 0 dns_resolver: foo.bar.com Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-and-Tested-by: Jeff Layton <jlayton@redhat.com> Acked-by: Steve French <smfrench@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-21[CIFS] Neaten cERROR and cFYI macros, reduce text spaceJoe Perches
Neaten cERROR and cFYI macros, reduce text space ~2.5K Convert '__FILE__ ": " fmt' to '"%s: " fmt', __FILE__' to save text space Surround macros with do {} while Add parentheses to macros Make statement expression macro from macro with assign Remove now unnecessary parentheses from cFYI and cERROR uses defconfig with CIFS support old $ size fs/cifs/built-in.o text data bss dec hex filename 156012 1760 148 157920 268e0 fs/cifs/built-in.o defconfig with CIFS support old $ size fs/cifs/built-in.o text data bss dec hex filename 153508 1760 148 155416 25f18 fs/cifs/built-in.o allyesconfig old: $ size fs/cifs/built-in.o text data bss dec hex filename 309138 3864 74824 387826 5eaf2 fs/cifs/built-in.o allyesconfig new $ size fs/cifs/built-in.o text data bss dec hex filename 305655 3864 74824 384343 5dd57 fs/cifs/built-in.o Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2009-06-25cifs: have cifs parse scope_id out of IPv6 addresses and use itJeff Layton
This patch has CIFS look for a '%' in an IPv6 address. If one is present then it will try to treat that value as a numeric interface index suitable for stuffing into the sin6_scope_id field. This should allow people to mount servers on IPv6 link-local addresses. Signed-off-by: Jeff Layton <jlayton@redhat.com> Acked-by: David Holder <david@erion.co.uk> Signed-off-by: Steve French <sfrench@us.ibm.com>
2009-06-13cifs: add new routine for converting AF_INET and AF_INET6 addrsJeff Layton
...to consolidate some logic used in more than one place. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
2009-04-17cifs: no need to use rcu_assign_pointer on immutable keysJeff Layton
cifs: no need to use rcu_assign_pointer on immutable keys Neither keytype in use by CIFS has an "update" method. This means that the keys are immutable once instantiated. We don't need to use RCU to set the payload data pointers. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
2008-09-23[CIFS] clean up upcall handling for dns_resolver keysSteve French
We're given the datalen in the downcall, so there's no need to do any calls to strlen(). Just keep track of the datalen in the key. Finally, add a sanity check of the data in the downcall to make sure that it looks like a real IP address. Signed-off-by: Jeff Layton <jlayton@redhat.com> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
2008-08-27[CIFS] Add destroy routine for dns_resolverJeff Layton
Otherwise, we're leaking the payload memory. CC: Stable Kernel <stable@vger.kernel.org> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
2008-05-21Fix possible access to undefined memory region.Igor Mammedov
Signed-off-by: Igor Mammedov <niallain@gmail.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
2008-04-26[CIFS] Adds to dns_resolver checking if the server name is an IP addr and ↵Steve French
skipping upcall in this case. Signed-off-by: Igor Mammedov <niallain@gmail.com> Signed-off-by: sfrench@us.ibm.com
2008-03-10[CIFS] cifs: replace remaining __FUNCTION__ occurrencesHarvey Harrison
__FUNCTION__ is gcc-specific, use __func__ Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
2008-01-25[CIFS] DFS build fixesSteve French
Also includes a few minor changes suggested by Christoph Signed-off-by: Steve French <sfrench@us.ibm.com>
2008-01-10[CIFS] Forgot to add two new files from previous commitSteve French
Thanks to Igor for noticing this. CC: Igor Mammedov <niallain@gmail.com> Signed-off-by: Steve French <sfrench@us.ibm.com>