From 8c8c32339ae965fa6991462e98be1f5890ac7499 Mon Sep 17 00:00:00 2001 From: Michal Privoznik Date: Tue, 26 Jun 2018 15:34:21 +0200 Subject: [PATCH] qemuDomainSaveMemory: Don't enforce dynamicOwnership https://bugzilla.redhat.com/show_bug.cgi?id=1589115 When doing a memory snapshot qemuOpenFile() is used. This means that the file where memory is saved is firstly attempted to be created under root:root (because that's what libvirtd is running under) and if this fails the second attempt is done under domain's uid:gid. This does not make much sense - qemu is given opened FD so it does not need to access the file. Moreover, if dynamicOwnership is set in qemu.conf and the file lives on a squashed NFS this is deadly combination and very likely to fail. The fix consists of using: qemuOpenFileAs(fallback_uid = cfg->user, fallback_gid = cfg->group, dynamicOwnership = false) In other words, dynamicOwnership is turned off for memory snapshot (chown() will still be attempted if the file does not live on NFS) and instead of using domain DAC label, configured user:group is set as fallback. Signed-off-by: Michal Privoznik Reviewed-by: Michal Privoznik --- src/qemu/qemu_driver.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index ca04be30c8..4e2aea0db0 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -3185,6 +3185,7 @@ qemuDomainSaveMemory(virQEMUDriverPtr driver, unsigned int flags, qemuDomainAsyncJob asyncJob) { + virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver); bool needUnlink = false; int ret = -1; int fd = -1; @@ -3202,9 +3203,10 @@ qemuDomainSaveMemory(virQEMUDriverPtr driver, goto cleanup; } } - fd = qemuOpenFile(driver, vm, path, - O_WRONLY | O_TRUNC | O_CREAT | directFlag, - &needUnlink); + + fd = qemuOpenFileAs(cfg->user, cfg->group, false, path, + O_WRONLY | O_TRUNC | O_CREAT | directFlag, + &needUnlink); if (fd < 0) goto cleanup; @@ -3244,6 +3246,7 @@ qemuDomainSaveMemory(virQEMUDriverPtr driver, cleanup: VIR_FORCE_CLOSE(fd); virFileWrapperFdFree(wrapperFd); + virObjectUnref(cfg); if (ret < 0 && needUnlink) unlink(path); @@ -3793,9 +3796,9 @@ doCoreDump(virQEMUDriverPtr driver, /* Core dumps usually imply last-ditch analysis efforts are * desired, so we intentionally do not unlink even if a file was * created. */ - if ((fd = qemuOpenFile(driver, vm, path, - O_CREAT | O_TRUNC | O_WRONLY | directFlag, - NULL)) < 0) + if ((fd = qemuOpenFileAs(cfg->user, cfg->group, false, path, + O_CREAT | O_TRUNC | O_WRONLY | directFlag, + NULL)) < 0) goto cleanup; if (!(wrapperFd = virFileWrapperFdNew(&fd, path, flags)))