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2021-02-16viriofsd: Add support for FUSE_HANDLE_KILLPRIV_V2Vivek Goyal
This patch adds basic support for FUSE_HANDLE_KILLPRIV_V2. virtiofsd can enable/disable this by specifying option "-o killpriv_v2/no_killpriv_v2". By default this is enabled as long as client supports it Enabling this option helps with performance in write path. Without this option, currently every write is first preceeded with a getxattr() operation to find out if security.capability is set. (Write is supposed to clear security.capability). With this option enabled, server is signing up for clearing security.capability on every WRITE and also clearing suid/sgid subject to certain rules. This gets rid of extra getxattr() call for every WRITE and improves performance. This is true when virtiofsd is run with option -o xattr. What does enabling FUSE_HANDLE_KILLPRIV_V2 mean for file server implementation. It needs to adhere to following rules. Thanks to Miklos for this summary. - clear "security.capability" on write, truncate and chown unconditionally - clear suid/sgid in case of following. Note, sgid is cleared only if group executable bit is set. o setattr has FATTR_SIZE and FATTR_KILL_SUIDGID set. o setattr has FATTR_UID or FATTR_GID o open has O_TRUNC and FUSE_OPEN_KILL_SUIDGID o create has O_TRUNC and FUSE_OPEN_KILL_SUIDGID flag set. o write has FUSE_WRITE_KILL_SUIDGID >From Linux VFS client perspective, here are the requirements. - caps are always cleared on chown/write/truncate - suid is always cleared on chown, while for truncate/write it is cleared only if caller does not have CAP_FSETID. - sgid is always cleared on chown, while for truncate/write it is cleared only if caller does not have CAP_FSETID as well as file has group execute permission. virtiofsd implementation has not changed much to adhere to above ruls. And reason being that current assumption is that we are running on Linux and on top of filesystems like ext4/xfs which already follow above rules. On write, truncate, chown, seucurity.capability is cleared. And virtiofsd drops CAP_FSETID if need be and that will lead to clearing of suid/sgid. But if virtiofsd is running on top a filesystem which breaks above assumptions, then it will have to take extra actions to emulate above. That's a TODO for later when need arises. Note: create normally is supposed to be called only when file does not exist. So generally there should not be any question of clearing setuid/setgid. But it is possible that after client checks that file is not present, some other client creates file on server and this race can trigger sending FUSE_CREATE. In that case, if O_TRUNC is set, we should clear suid/sgid if FUSE_OPEN_KILL_SUIDGID is also set. v3: - Resolved conflicts due to lo_inode_open() changes. - Moved capability code in lo_do_open() so that both lo_open() and lo_create() can benefit from common code. - Dropped changes to kernel headers as these are part of qemu already. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20210208224024.43555-3-vgoyal@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-12-15virtiofsd: replace _Static_assert with QEMU_BUILD_BUG_ONMarc-André Lureau
This allows to get rid of a check for older GCC version (which was a bit bogus too since it was falling back on c++ version..) Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20201210134752.780923-7-marcandre.lureau@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-12-10Clean up includesMarkus Armbruster
Clean up includes so that osdep.h is included first and headers which it implies are not included manually. This commit was created with scripts/clean-includes, with the changes to the following files manually reverted: contrib/libvhost-user/libvhost-user-glib.h contrib/libvhost-user/libvhost-user.c contrib/libvhost-user/libvhost-user.h contrib/plugins/hotblocks.c contrib/plugins/hotpages.c contrib/plugins/howvec.c contrib/plugins/lockstep.c linux-user/mips64/cpu_loop.c linux-user/mips64/signal.c linux-user/sparc64/cpu_loop.c linux-user/sparc64/signal.c linux-user/x86_64/cpu_loop.c linux-user/x86_64/signal.c target/s390x/gen-features.c tests/fp/platform.h tests/migration/s390x/a-b-bios.c tests/plugin/bb.c tests/plugin/empty.c tests/plugin/insn.c tests/plugin/mem.c tests/test-rcu-simpleq.c tests/test-rcu-slist.c tests/test-rcu-tailq.c tests/uefi-test-tools/UefiTestToolsPkg/BiosTablesTest/BiosTablesTest.c contrib/plugins/, tests/plugin/, and tests/test-rcu-slist.c appear not to include osdep.h intentionally. The remaining reverts are the same as in commit bbfff19688d. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20201113061216.2483385-1-armbru@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Tested-by: Thomas Huth <thuth@redhat.com> Acked-by: Cornelia Huck <cohuck@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Acked-by: Alexander Bulekov <alxndr@bu.edu>
2020-11-02virtiofsd: Check FUSE_SUBMOUNTSMax Reitz
FUSE_SUBMOUNTS is a pure indicator by the kernel to signal that it supports submounts. It does not check its state in the init reply, so there is nothing for fuse_lowlevel.c to do but to check its existence and copy it into fuse_conn_info.capable. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20201102161859.156603-2-mreitz@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-10-28Revert series: virtiofsd: Announce submounts to the guestAlex Williamson
This reverts the following commits due to their basis on a bogus linux kernel header update: c93a656f7b65 ("tests/acceptance: Add virtiofs_submounts.py") 45ced7ca2f27 ("tests/acceptance/boot_linux: Accept SSH pubkey") 08dce386e77e ("virtiofsd: Announce sub-mount points") eba8b096c17c ("virtiofsd: Store every lo_inode's parent_dev") ede24b6be798 ("virtiofsd: Add fuse_reply_attr_with_flags()") e2577435d343 ("virtiofsd: Add attr_flags to fuse_entry_param") 2f10415abfc5 ("virtiofsd: Announce FUSE_ATTR_FLAGS") 97d741cc96dd ("linux/fuse.h: Pull in from Linux") Cc: Max Reitz <mreitz@redhat.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Cc: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 160385090886.20017.13382256442750027666.stgit@gimli.home Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2020-10-26virtiofsd: Announce FUSE_ATTR_FLAGSMax Reitz
The fuse_attr.flags field is currently just initialized to 0, which is valid. Thus, there is no reason not to always announce FUSE_ATTR_FLAGS (when the kernel supports it). Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200909184028.262297-3-mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-01-23virtiofsd: Parse flag FUSE_WRITE_KILL_PRIVVivek Goyal
Caller can set FUSE_WRITE_KILL_PRIV in write_flags. Parse it and pass it to the filesystem. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com> Reviewed-by: Sergio Lopez <slp@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-01-23virtiofsd: add fuse_mbuf_iter APIStefan Hajnoczi
Introduce an API for consuming bytes from a buffer with size checks. All FUSE operations will be converted to use this safe API instead of void *inarg. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-01-23virtiofsd: Remove unused enum fuse_buf_copy_flagsXiao Yang
Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-01-23virtiofsd: Format imported files to qemu styleDr. David Alan Gilbert
Mostly using a set like: indent -nut -i 4 -nlp -br -cs -ce --no-space-after-function-call-names file clang-format -style=file -i -- file clang-tidy -fix-errors -checks=readability-braces-around-statements file clang-format -style=file -i -- file With manual cleanups. The .clang-format used is below. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed by: Aleksandar Markovic <amarkovic@wavecomp.com> Language: Cpp AlignAfterOpenBracket: Align AlignConsecutiveAssignments: false # although we like it, it creates churn AlignConsecutiveDeclarations: false AlignEscapedNewlinesLeft: true AlignOperands: true AlignTrailingComments: false # churn AllowAllParametersOfDeclarationOnNextLine: true AllowShortBlocksOnASingleLine: false AllowShortCaseLabelsOnASingleLine: false AllowShortFunctionsOnASingleLine: None AllowShortIfStatementsOnASingleLine: false AllowShortLoopsOnASingleLine: false AlwaysBreakAfterReturnType: None # AlwaysBreakAfterDefinitionReturnType is taken into account AlwaysBreakBeforeMultilineStrings: false BinPackArguments: true BinPackParameters: true BraceWrapping: AfterControlStatement: false AfterEnum: false AfterFunction: true AfterStruct: false AfterUnion: false BeforeElse: false IndentBraces: false BreakBeforeBinaryOperators: None BreakBeforeBraces: Custom BreakBeforeTernaryOperators: false BreakStringLiterals: true ColumnLimit: 80 ContinuationIndentWidth: 4 Cpp11BracedListStyle: false DerivePointerAlignment: false DisableFormat: false ForEachMacros: [ 'CPU_FOREACH', 'CPU_FOREACH_REVERSE', 'CPU_FOREACH_SAFE', 'IOMMU_NOTIFIER_FOREACH', 'QLIST_FOREACH', 'QLIST_FOREACH_ENTRY', 'QLIST_FOREACH_RCU', 'QLIST_FOREACH_SAFE', 'QLIST_FOREACH_SAFE_RCU', 'QSIMPLEQ_FOREACH', 'QSIMPLEQ_FOREACH_SAFE', 'QSLIST_FOREACH', 'QSLIST_FOREACH_SAFE', 'QTAILQ_FOREACH', 'QTAILQ_FOREACH_REVERSE', 'QTAILQ_FOREACH_SAFE', 'QTAILQ_RAW_FOREACH', 'RAMBLOCK_FOREACH' ] IncludeCategories: - Regex: '^"qemu/osdep.h' Priority: -3 - Regex: '^"(block|chardev|crypto|disas|exec|fpu|hw|io|libdecnumber|migration|monitor|net|qapi|qemu|qom|standard-headers|sysemu|ui)/' Priority: -2 - Regex: '^"(elf.h|qemu-common.h|glib-compat.h|qemu-io.h|trace-tcg.h)' Priority: -1 - Regex: '.*' Priority: 1 IncludeIsMainRegex: '$' IndentCaseLabels: false IndentWidth: 4 IndentWrappedFunctionNames: false KeepEmptyLinesAtTheStartOfBlocks: false MacroBlockBegin: '.*_BEGIN$' # only PREC_BEGIN ? MacroBlockEnd: '.*_END$' MaxEmptyLinesToKeep: 2 PointerAlignment: Right ReflowComments: true SortIncludes: true SpaceAfterCStyleCast: false SpaceBeforeAssignmentOperators: true SpaceBeforeParens: ControlStatements SpaceInEmptyParentheses: false SpacesBeforeTrailingComments: 1 SpacesInContainerLiterals: true SpacesInParentheses: false SpacesInSquareBrackets: false Standard: Auto UseTab: Never ... Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-01-23virtiofsd: Trim down imported filesDr. David Alan Gilbert
There's a lot of the original fuse code we don't need; trim them down. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> with additional trimming by: Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Xiao Yang <yangx.jy@cn.fujitsu.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-01-23virtiofsd: Pull in upstream headersDr. David Alan Gilbert
Pull in headers fromlibfuse's upstream fuse-3.8.0 Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>