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| author | Roland Shoemaker <roland@golang.org> | 2025-10-23 08:16:39 -0700 |
|---|---|---|
| committer | Michael Knyszek <mknyszek@google.com> | 2025-10-29 09:22:37 -0700 |
| commit | 83885f3c22242f3e4499bb5b12892bc7ba11a74b (patch) | |
| tree | d1a16d093dbc3d90933e9baa4f81558e2ea06be7 | |
| parent | 5ba37a3677d322c442ab77f94d4f92f1acc67dba (diff) | |
| download | go-83885f3c22242f3e4499bb5b12892bc7ba11a74b.tar.xz | |
[release-branch.go1.25] encoding/pem: properly calculate end indexes
When a block is missing the END line trailer, calculate the indexes of
the end and end trailer _before_ continuing the loop, making the
reslicing at the start of the loop work as expected.
Fixes #76029
Change-Id: If45c8cb473315623618f02cc7609f517a72d232d
Reviewed-on: https://go-review.googlesource.com/c/go/+/714200
Auto-Submit: Roland Shoemaker <roland@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
(cherry picked from commit 839da71f8907ac4434299db4353db31835c916df)
Reviewed-on: https://go-review.googlesource.com/c/go/+/714661
Reviewed-by: David Chase <drchase@google.com>
| -rw-r--r-- | src/encoding/pem/pem.go | 7 | ||||
| -rw-r--r-- | src/encoding/pem/pem_test.go | 4 |
2 files changed, 9 insertions, 2 deletions
diff --git a/src/encoding/pem/pem.go b/src/encoding/pem/pem.go index 2356096ade..6bf2b41ad0 100644 --- a/src/encoding/pem/pem.go +++ b/src/encoding/pem/pem.go @@ -95,6 +95,9 @@ func Decode(data []byte) (p *Block, rest []byte) { for { // If we've already tried parsing a block, skip past the END we already // saw. + if endTrailerIndex < 0 || endTrailerIndex > len(rest) { + return nil, data + } rest = rest[endTrailerIndex:] // Find the first END line, and then find the last BEGIN line before @@ -116,11 +119,11 @@ func Decode(data []byte) (p *Block, rest []byte) { var typeLine []byte var consumed int typeLine, rest, consumed = getLine(rest) + endIndex -= consumed + endTrailerIndex -= consumed if !bytes.HasSuffix(typeLine, pemEndOfLine) { continue } - endIndex -= consumed - endTrailerIndex -= consumed typeLine = typeLine[0 : len(typeLine)-len(pemEndOfLine)] p = &Block{ diff --git a/src/encoding/pem/pem_test.go b/src/encoding/pem/pem_test.go index 5bdc2f66a7..fa6e8ba62b 100644 --- a/src/encoding/pem/pem_test.go +++ b/src/encoding/pem/pem_test.go @@ -736,3 +736,7 @@ func FuzzDecode(f *testing.F) { Decode(data) }) } + +func TestMissingEndTrailer(t *testing.T) { + Decode([]byte{0x2d, 0x2d, 0x2d, 0x2d, 0x2d, 0x42, 0x45, 0x47, 0x49, 0x4e, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0xa, 0x2d, 0x2d, 0x2d, 0x2d, 0x2d, 0x45, 0x4e, 0x44, 0x20}) +} |