# [JGIT PATCH 1/2] Fix the UnpackedObjectCache hash function to prevent overflow 2 messages from 2008-09-30 to 2008-09-30. Participants: Shawn O. Pearce. Thread: https://gitlist.dev/t/15718 ## Shawn O. Pearce, 2008-09-30 07:47 Subject: [JGIT PATCH 1/2] Fix the UnpackedObjectCache hash function to prevent overflow Message-ID: <1222760871-58768-1-git-send-email-spearce@spearce.org> URL: https://gitlist.dev/e/1222760871-58768-1-git-send-email-spearce%40spearce.org ``` Sometimes we got negative array indexes inside of the cache due to WindowedFile.hash having a negative value assigned by the JVM. We now use only the lower 8 bits as the cache is fixed to at most 256 entries. Signed-off-by: Shawn O. Pearce --- .../org/spearce/jgit/lib/UnpackedObjectCache.java | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff --git a/org.spearce.jgit/src/org/spearce/jgit/lib/UnpackedObjectCache.java b/org.spearce.jgit/src/org/spearce/jgit/lib/UnpackedObjectCache.java index 03cf674..ee6a680 100644 --- a/org.spearce.jgit/src/org/spearce/jgit/lib/UnpackedObjectCache.java +++ b/org.spearce.jgit/src/org/spearce/jgit/lib/UnpackedObjectCache.java @@ -48,9 +48,9 @@ private static int hash(final WindowedFile pack, final long position) { int h = pack.hash + (int) position; - h += h >> 16; - h += h >> 8; - return h % CACHE_SZ; + h += h >>> 16; + h += h >>> 8; + return h & (CACHE_SZ - 1); } private static int maxByteCount; -- 1.6.0.2.463.g7f0eb ``` ## Shawn O. Pearce, 2008-09-30 07:47 Subject: [JGIT PATCH 2/2] ObjectId: Convert StringIndexOutOfBounds to IllegalArgumentException Message-ID: <1222760871-58768-2-git-send-email-spearce@spearce.org> URL: https://gitlist.dev/e/1222760871-58768-2-git-send-email-spearce%40spearce.org In-Reply-To: <1222760871-58768-1-git-send-email-spearce@spearce.org> ``` If parsing an ObjectId fromString fails because the string is too short we don't want to throw StringIndexOutOfBoundsException with a trace that leads back to the error handling code; instead we should throw what the caller expects us to throw, which is IllegalArgumentException. Signed-off-by: Shawn O. Pearce --- .../src/org/spearce/jgit/lib/MutableObjectId.java | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/org.spearce.jgit/src/org/spearce/jgit/lib/MutableObjectId.java b/org.spearce.jgit/src/org/spearce/jgit/lib/MutableObjectId.java index f88d8cb..5b16345 100644 --- a/org.spearce.jgit/src/org/spearce/jgit/lib/MutableObjectId.java +++ b/org.spearce.jgit/src/org/spearce/jgit/lib/MutableObjectId.java @@ -161,6 +161,8 @@ private void fromHexString(final byte[] bs, int p) { throw new IllegalArgumentException("Invalid id: " + str); } catch (UnsupportedEncodingException e2) { throw new IllegalArgumentException("Invalid id"); + } catch (StringIndexOutOfBoundsException e2) { + throw new IllegalArgumentException("Invalid id"); } } } -- 1.6.0.2.463.g7f0eb ```