From e9f5e7081c62a47fb875569403e37cacca26dc12 Mon Sep 17 00:00:00 2001 From: Daniel Verkamp Date: Fri, 4 Oct 2019 12:31:32 -0700 Subject: Fix sparse file offset overflow on 32-bit systems On architectures where ssize_t is 32 bits but file offsets are 64 bits (such as 32-bit Linux with _FILE_OFFSET_BITS=64), the POSIX disk reader would incorrectly skip large sparse regions due to a 32-bit integer overflow in _archive_read_data_block(). This can result in the reader failing with "Encountered out-of-order sparse blocks", since the overflowed value is interpreted as a signed number and added to the current offset. The bytes variable was used to store the difference between two 64-bit integers, but bytes is a ssize_t. Since this value of bytes was not used after the block handling sparse offsets (it is always overwritten in the block below), replace it with an int64_t sparse_bytes variable that can always represent the difference without truncation. Signed-off-by: Daniel Verkamp --- libarchive/archive_read_disk_posix.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'libarchive/archive_read_disk_posix.c') diff --git a/libarchive/archive_read_disk_posix.c b/libarchive/archive_read_disk_posix.c index 87963c3c..f62d182e 100644 --- a/libarchive/archive_read_disk_posix.c +++ b/libarchive/archive_read_disk_posix.c @@ -694,6 +694,7 @@ _archive_read_data_block(struct archive *_a, const void **buff, struct tree *t = a->tree; int r; ssize_t bytes; + int64_t sparse_bytes; size_t buffbytes; int empty_sparse_region = 0; @@ -792,9 +793,9 @@ _archive_read_data_block(struct archive *_a, const void **buff, a->archive.state = ARCHIVE_STATE_FATAL; goto abort_read_data; } - bytes = t->current_sparse->offset - t->entry_total; - t->entry_remaining_bytes -= bytes; - t->entry_total += bytes; + sparse_bytes = t->current_sparse->offset - t->entry_total; + t->entry_remaining_bytes -= sparse_bytes; + t->entry_total += sparse_bytes; } /* -- cgit v1.2.1