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path: root/fs/cifs/dns_resolve.c
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2021-07-14cifs: use the expiry output of dns_query to schedule next resolutionShyam Prasad N1-4/+6
We recently fixed DNS resolution of the server hostname during reconnect. However, server IP address may change, even when the old one continues to server (although sub-optimally). We should schedule the next DNS resolution based on the TTL of the DNS record used for the last resolution. This way, we resolve the server hostname again when a DNS record expires. Signed-off-by: Shyam Prasad N <sprasad@microsoft.com> Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Cc: <stable@vger.kernel.org> # v5.11+ Signed-off-by: Steve French <stfrench@microsoft.com>
2021-06-20cifs: use SPDX-Licence-IdentifierSteve French1-13/+1
Add SPDX license identifier and replace license boilerplate. Corrects various checkpatch errors with the older format for noting the LGPL license. Signed-off-by: Steve French <stfrench@microsoft.com>
2019-06-27keys: Pass the network namespace into request_key mechanismDavid Howells1-1/+2
Create a request_key_net() function and use it to pass the network namespace domain tag into DNS revolver keys and rxrpc/AFS keys so that keys for different domains can coexist in the same keyring. Signed-off-by: David Howells <dhowells@redhat.com> cc: netdev@vger.kernel.org cc: linux-nfs@vger.kernel.org cc: linux-cifs@vger.kernel.org cc: linux-afs@lists.infradead.org
2019-05-15dns_resolver: Allow used keys to be invalidatedDavid Howells1-1/+1
Allow used DNS resolver keys to be invalidated after use if the caller is doing its own caching of the results. This reduces the amount of resources required. Fix AFS to invalidate DNS results to kill off permanent failure records that get lodged in the resolver keyring and prevent future lookups from happening. Fixes: 0a5143f2f89c ("afs: Implement VL server rotation") Signed-off-by: David Howells <dhowells@redhat.com>
2013-05-24cifs: fix composing of mount options for DFS referralsJeff Layton1-2/+2
With the change to ignore the unc= and prefixpath= mount options, there is no longer any need to add them to the options string when mounting. By the same token, we now need to build a device name that includes the prefixpath when mounting. To make things neater, the delimiters on the devicename are changed to '/' since that's preferred when mounting anyway. v2: fix some comments and don't bother looking at whether there is a prepath in the ref->node_name when deciding whether to pass a prepath to cifs_build_devname. v3: rebase on top of potential buffer overrun fix for stable Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
2013-05-04[CIFS] cifs: Rename cERROR and cFYI to cifs_dbgJoe Perches1-8/+9
It's not obvious from reading the macro names that these macros are for debugging. Convert the names to a single more typical kernel style cifs_dbg macro. cERROR(1, ...) -> cifs_dbg(VFS, ...) cFYI(1, ...) -> cifs_dbg(FYI, ...) cFYI(DBG2, ...) -> cifs_dbg(NOISY, ...) Move the terminating format newline from the macro to the call site. Add CONFIG_CIFS_DEBUG function cifs_vfs_err to emit the "CIFS VFS: " prefix for VFS messages. Size is reduced ~ 1% when CONFIG_CIFS_DEBUG is set (default y) $ size fs/cifs/cifs.ko* text data bss dec hex filename 265245 2525 132 267902 4167e fs/cifs/cifs.ko.new 268359 2525 132 271016 422a8 fs/cifs/cifs.ko.old Other miscellaneous changes around these conversions: o Miscellaneous typo fixes o Add terminating \n's to almost all formats and remove them from the macros to be more kernel style like. A few formats previously had defective \n's o Remove unnecessary OOM messages as kmalloc() calls dump_stack o Coalesce formats to make grep easier, added missing spaces when coalescing formats o Use %s, __func__ instead of embedded function name o Removed unnecessary "cifs: " prefixes o Convert kzalloc with multiply to kcalloc o Remove unused cifswarn macro Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <smfrench@gmail.com>
2011-08-03cifs: demote DFS referral lookup errors to cFYIJeff Layton1-2/+2
cifs: demote DFS referral lookup errors to cFYI Now that we call into this routine on every mount, anyone who doesn't have the upcall configured will get multiple printks about failed lookups. Reported-and-Tested-by: Martijn Uffing <mp3project@sarijopen.student.utwente.nl> Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-11-30cifs: fix parsing of hostname in dfs referralsJeff Layton1-1/+1
The DFS referral parsing code does a memchr() call to find the '\\' delimiter that separates the hostname in the referral UNC from the sharename. It then uses that value to set the length of the hostname via pointer subtraction. Instead of subtracting the start of the hostname however, it subtracts the start of the UNC, which causes the code to pass in a hostname length that is 2 bytes too long. Regression introduced in commit 1a4240f4. Reported-and-Tested-by: Robbert Kouprie <robbert@exx.nl> Signed-off-by: Jeff Layton <jlayton@redhat.com> Cc: Wang Lei <wang840925@gmail.com> Cc: David Howells <dhowells@redhat.com> Cc: stable@kernel.org Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-05DNS: Separate out CIFS DNS Resolver codeWang Lei1-183/+46
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 Howells1-11/+9
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 Layton1-1/+1
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 Howells1-1/+1
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 Howells1-0/+69
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 Perches1-8/+8
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 Heo1-0/+1
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 Layton1-2/+2
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 Layton1-18/+3
...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 Layton1-1/+1
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 French1-33/+41
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 Layton1-0/+7
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 Mammedov1-4/+5
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 French1-10/+52
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 Harrison1-4/+4
__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 French1-2/+3
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 French1-0/+123
Thanks to Igor for noticing this. CC: Igor Mammedov <niallain@gmail.com> Signed-off-by: Steve French <sfrench@us.ibm.com>