netbird/gvisor
0
0
Fork 0
mirror of https://github.com/netbirdio/gvisor.git synced 2026-05-22 17:12:49 -07:00
Code Issues Packages Projects Releases Wiki Activity

Don't read beyond EOF when inserting into sentry page cache.

Browse Source 
The sentry page cache stores file contents at page granularity; this is
necessary for memory mappings. Thus file offset ranges passed to
fsutil.FileRangeSet.Fill() must be page-aligned. If the read callback passed to
Fill() returns (partial read, nil error) when reading up to EOF (which is the
case for p9.ClientFile.ReadAt() since 9P's Rread cannot convey both a partial
read and EOF), Fill() will re-invoke the read callback to try to read from EOF
to the end of the containing page, which is harmless but needlessly expensive.
Fix this by handling file size explicitly in fsutil.FileRangeSet.Fill().

PiperOrigin-RevId: 336934075
This commit is contained in:
Jamie Liu
2020-10-13 12:45:51 -07:00
committed by gVisor bot
parent 7053f17859
commit 1a69487373
5 changed files with 28 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files
pkg/sentry/fsimpl/tmpfs/regular_file.go
+1 -1
View File
@@ -293,7 +293,7 @@ func (rf *regularFile) Translate(ctx context.Context, required, optional memmap.
optional.End = pgend
}
cerr := rf.data.Fill(ctx, required, optional, rf.memFile, rf.memoryUsageKind, func(_ context.Context, dsts safemem.BlockSeq, _ uint64) (uint64, error) {
cerr := rf.data.Fill(ctx, required, optional, rf.size, rf.memFile, rf.memoryUsageKind, func(_ context.Context, dsts safemem.BlockSeq, _ uint64) (uint64, error) {
// Newly-allocated pages are zeroed, so we don't need to do anything.
return dsts.NumBytes(), nil
})