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[Qemu-block] [PATCH v1 3/8] dmg: Limit the output buffer size to a max o
From: |
Ashijeet Acharya |
Subject: |
[Qemu-block] [PATCH v1 3/8] dmg: Limit the output buffer size to a max of 2MB |
Date: |
Wed, 26 Apr 2017 01:29:06 +0530 |
The size of the output buffer is limited to a maximum of 2MB so that
QEMU doesn't end up allocating huge amounts of memory while
decompressing compressed input streams.
2MB is an appropriate size because "qemu-img convert" has the same I/O
buffer size and the most important use case for DMG files is to be
compatible with qemu-img convert.
Signed-off-by: Ashijeet Acharya <address@hidden>
---
block/dmg.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/block/dmg.c b/block/dmg.c
index c6fe8b0..7ae30e3 100644
--- a/block/dmg.c
+++ b/block/dmg.c
@@ -37,8 +37,8 @@ enum {
/* Limit chunk sizes to prevent unreasonable amounts of memory being used
* or truncating when converting to 32-bit types
*/
- DMG_LENGTHS_MAX = 64 * 1024 * 1024, /* 64 MB */
- DMG_SECTORCOUNTS_MAX = DMG_LENGTHS_MAX / 512,
+ DMG_MAX_OUTPUT = 2 * 1024 * 1024, /* 2 MB */
+ DMG_SECTOR_MAX = DMG_MAX_OUTPUT / 512,
};
static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename)
@@ -260,10 +260,10 @@ static int dmg_read_mish_block(BDRVDMGState *s,
DmgHeaderState *ds,
/* all-zeroes sector (type 2) does not need to be "uncompressed" and
can
* therefore be unbounded. */
- if (s->types[i] != 2 && s->sectorcounts[i] > DMG_SECTORCOUNTS_MAX) {
+ if (s->types[i] != 2 && s->sectorcounts[i] > DMG_SECTOR_MAX) {
error_report("sector count %" PRIu64 " for chunk %" PRIu32
" is larger than max (%u)",
- s->sectorcounts[i], i, DMG_SECTORCOUNTS_MAX);
+ s->sectorcounts[i], i, DMG_SECTOR_MAX);
ret = -EINVAL;
goto fail;
}
@@ -275,10 +275,10 @@ static int dmg_read_mish_block(BDRVDMGState *s,
DmgHeaderState *ds,
/* length in (compressed) data fork */
s->lengths[i] = buff_read_uint64(buffer, offset + 0x20);
- if (s->lengths[i] > DMG_LENGTHS_MAX) {
+ if (s->lengths[i] > DMG_MAX_OUTPUT) {
error_report("length %" PRIu64 " for chunk %" PRIu32
" is larger than max (%u)",
- s->lengths[i], i, DMG_LENGTHS_MAX);
+ s->lengths[i], i, DMG_MAX_OUTPUT);
ret = -EINVAL;
goto fail;
}
--
2.6.2
- [Qemu-block] [PATCH v1 0/8] Refactor DMG driver to have chunk size independence, Ashijeet Acharya, 2017/04/25
- [Qemu-block] [PATCH v1 4/8] dmg: Refactor and prepare dmg_read_chunk() to cache random access points, Ashijeet Acharya, 2017/04/25
- [Qemu-block] [PATCH v1 5/8] dmg: Handle zlib compressed chunks, Ashijeet Acharya, 2017/04/25
- [Qemu-block] [PATCH v1 6/8] dmg: Handle bz2 compressed/raw/zeroed chunks, Ashijeet Acharya, 2017/04/25
- [Qemu-block] [PATCH v1 7/8] dmg: Refactor dmg_co_preadv() to start reading multiple sectors, Ashijeet Acharya, 2017/04/25
- [Qemu-block] [PATCH v1 8/8] dmg: Remove the error messages to allow wild images, Ashijeet Acharya, 2017/04/25