Since
commit 432faf259b696043ee5d7e8f657d855419a9a3fa
Author: Michal Privoznik <mprivozn@xxxxxxxxxx>
Date: Tue Jul 2 19:49:51 2019 +0200
virCommand: use procfs to learn opened FDs
When spawning a child process, between fork() and exec() we close
all file descriptors and keep only those the caller wants us to
pass onto the child. The problem is how we do that. Currently, we
get the limit of opened files and then iterate through each one
of them and either close() it or make it survive exec(). This
approach is suboptimal (although, not that much in default
configurations where the limit is pretty low - 1024). We have
/proc where we can learn what FDs we hold open and thus we can
selectively close only those.
Signed-off-by: Michal Privoznik <mprivozn@xxxxxxxxxx>
Reviewed-by: Ján Tomko <jtomko@xxxxxxxxxx>
v5.5.0-173-g432faf259b
programs using the virCommand APIs on Linux need read access to
/proc/self/fd, or they will fail like
error : virCommandWait:2796 : internal error: Child process
(LIBVIRT_LOG_OUTPUTS=3:stderr /usr/lib/libvirt/virt-aa-helper -c
-u libvirt-b20e9a8e-091a-45e0-8823-537119e98bc6) unexpected exit
status 1: libvirt: error : cannot open directory '/proc/self/fd':
Permission denied
virt-aa-helper: error: apparmor_parser exited with error
Update the AppArmor profile for virt-aa-helper so that read access
to the relevant path is granted.
Signed-off-by: Andrea Bolognani <abologna@xxxxxxxxxx>
---
src/security/apparmor/usr.lib.libvirt.virt-aa-helper | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/src/security/apparmor/usr.lib.libvirt.virt-aa-helper b/src/security/apparmor/usr.lib.libvirt.virt-aa-helper
index bf6bd297d1..d81dddef30 100644
--- a/src/security/apparmor/usr.lib.libvirt.virt-aa-helper
+++ b/src/security/apparmor/usr.lib.libvirt.virt-aa-helper
@@ -17,6 +17,10 @@ profile virt-aa-helper /usr/{lib,lib64}/libvirt/virt-aa-helper {
owner @{PROC}/[0-9]*/status r,
@{PROC}/filesystems r,
+ # Used when internally running another command (namely apparmor_parser)
+ @{PROC}/self/fd r,
+ @{PROC}/@{pid}/fd r,
+
/etc/libnl-3/classid r,
# for gl enabled graphics
--
2.21.0
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