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-rw-r--r--pkg/sentry/fs/proc/sys.go22
-rw-r--r--pkg/sentry/fsimpl/proc/tasks_sys.go1
-rw-r--r--test/syscalls/linux/proc.cc9
3 files changed, 32 insertions, 0 deletions
diff --git a/pkg/sentry/fs/proc/sys.go b/pkg/sentry/fs/proc/sys.go
index b998fb75d..085aa6d61 100644
--- a/pkg/sentry/fs/proc/sys.go
+++ b/pkg/sentry/fs/proc/sys.go
@@ -77,6 +77,27 @@ func (*overcommitMemory) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandl
}, 0
}
+// +stateify savable
+type maxMapCount struct{}
+
+// NeedsUpdate implements seqfile.SeqSource.
+func (*maxMapCount) NeedsUpdate(int64) bool {
+ return true
+}
+
+// ReadSeqFileData implements seqfile.SeqSource.
+func (*maxMapCount) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]seqfile.SeqData, int64) {
+ if h != nil {
+ return nil, 0
+ }
+ return []seqfile.SeqData{
+ {
+ Buf: []byte("2147483647\n"),
+ Handle: (*maxMapCount)(nil),
+ },
+ }, 0
+}
+
func (p *proc) newKernelDir(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
h := hostname{
SimpleFileInode: *fsutil.NewSimpleFileInode(ctx, fs.RootOwner, fs.FilePermsFromMode(0444), linux.PROC_SUPER_MAGIC),
@@ -96,6 +117,7 @@ func (p *proc) newKernelDir(ctx context.Context, msrc *fs.MountSource) *fs.Inode
func (p *proc) newVMDir(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
children := map[string]*fs.Inode{
+ "max_map_count": seqfile.NewSeqFileInode(ctx, &maxMapCount{}, msrc),
"mmap_min_addr": seqfile.NewSeqFileInode(ctx, &mmapMinAddrData{p.k}, msrc),
"overcommit_memory": seqfile.NewSeqFileInode(ctx, &overcommitMemory{}, msrc),
}
diff --git a/pkg/sentry/fsimpl/proc/tasks_sys.go b/pkg/sentry/fsimpl/proc/tasks_sys.go
index 88ab49048..2bc98a94f 100644
--- a/pkg/sentry/fsimpl/proc/tasks_sys.go
+++ b/pkg/sentry/fsimpl/proc/tasks_sys.go
@@ -55,6 +55,7 @@ func (fs *filesystem) newSysDir(ctx context.Context, root *auth.Credentials, k *
}),
}),
"vm": fs.newStaticDir(ctx, root, map[string]kernfs.Inode{
+ "max_map_count": fs.newInode(ctx, root, 0444, newStaticFile("2147483647\n")),
"mmap_min_addr": fs.newInode(ctx, root, 0444, &mmapMinAddrData{k: k}),
"overcommit_memory": fs.newInode(ctx, root, 0444, newStaticFile("0\n")),
}),
diff --git a/test/syscalls/linux/proc.cc b/test/syscalls/linux/proc.cc
index 24928d876..78aa73edc 100644
--- a/test/syscalls/linux/proc.cc
+++ b/test/syscalls/linux/proc.cc
@@ -2364,6 +2364,15 @@ TEST(ProcSysKernelHostname, MatchesUname) {
EXPECT_EQ(procfs_hostname, hostname);
}
+TEST(ProcSysVmMaxmapCount, HasNumericValue) {
+ const std::string val_str =
+ ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/sys/vm/max_map_count"));
+ int32_t val;
+ EXPECT_TRUE(absl::SimpleAtoi(val_str, &val))
+ << "/proc/sys/vm/max_map_count does not contain a numeric value: "
+ << val_str;
+}
+
TEST(ProcSysVmMmapMinAddr, HasNumericValue) {
const std::string mmap_min_addr_str =
ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/sys/vm/mmap_min_addr"));