summaryrefslogtreecommitdiffstats
path: root/src
diff options
context:
space:
mode:
authorSimon Rettberg2022-02-08 10:46:04 +0100
committerSimon Rettberg2022-03-04 12:04:14 +0100
commitc70bade50e275f901e63d7564e99a7bdabe83509 (patch)
treed5f16ed7b16c8b7b5f8f25fa5e54fda72a693b8b /src
parentREADME.md: State that qcow2 is read only (diff)
downloadxloop-c70bade50e275f901e63d7564e99a7bdabe83509.tar.gz
xloop-c70bade50e275f901e63d7564e99a7bdabe83509.tar.xz
xloop-c70bade50e275f901e63d7564e99a7bdabe83509.zip
Don't add byte offset to kmapped pointer
While the kunmap functions always round down to the current page, and currently, we never map a region larger than a page, it should be safer to do the pointer arithmetic after we acquired the mapped pointer, to avoid the risk of ever passing an invalid pointer to kunmap.
Diffstat (limited to 'src')
-rw-r--r--src/kernel/xloop_file_fmt_qcow_main.c22
1 files changed, 11 insertions, 11 deletions
diff --git a/src/kernel/xloop_file_fmt_qcow_main.c b/src/kernel/xloop_file_fmt_qcow_main.c
index 4fc2fe3..767698b 100644
--- a/src/kernel/xloop_file_fmt_qcow_main.c
+++ b/src/kernel/xloop_file_fmt_qcow_main.c
@@ -975,16 +975,16 @@ static int __qcow_file_fmt_read_compressed(struct xloop_file_fmt *xlo_fmt, struc
ASSERT(bytes <= bvec->bv_len);
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 15, 0)
- data = bvec_kmap_local(bvec) + bytes_done;
+ data = bvec_kmap_local(bvec);
#else
- data = bvec_kmap_irq(bvec, &irq_flags) + bytes_done;
+ data = bvec_kmap_irq(bvec, &irq_flags);
#endif
- memcpy(data, qcow_data->cmp_out_buf + offset_in_cluster, bytes);
+ memcpy(data + bytes_done, qcow_data->cmp_out_buf + offset_in_cluster, bytes);
flush_dcache_page(bvec->bv_page);
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 15, 0)
- kunmap_local(data);
+ kunmap_local(data);
#else
- bvec_kunmap_irq(data, &irq_flags);
+ bvec_kunmap_irq(data, &irq_flags);
#endif
out_free_in_buf:
@@ -1029,11 +1029,11 @@ static int __qcow_file_fmt_read_bvec(struct xloop_file_fmt *xlo_fmt, struct bio_
case QCOW_SUBCLUSTER_UNALLOCATED_PLAIN:
case QCOW_SUBCLUSTER_UNALLOCATED_ALLOC:
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 15, 0)
- data = bvec_kmap_local(bvec) + bytes_done;
+ data = bvec_kmap_local(bvec);
#else
- data = bvec_kmap_irq(bvec, &irq_flags) + bytes_done;
+ data = bvec_kmap_irq(bvec, &irq_flags);
#endif
- memset(data, 0, cur_bytes);
+ memset(data + bytes_done, 0, cur_bytes);
flush_dcache_page(bvec->bv_page);
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 15, 0)
kunmap_local(data);
@@ -1053,11 +1053,11 @@ static int __qcow_file_fmt_read_bvec(struct xloop_file_fmt *xlo_fmt, struct bio_
pos_read = host_offset;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 15, 0)
- data = bvec_kmap_local(bvec) + bytes_done;
+ data = bvec_kmap_local(bvec);
#else
- data = bvec_kmap_irq(bvec, &irq_flags) + bytes_done;
+ data = bvec_kmap_irq(bvec, &irq_flags);
#endif
- len = kernel_read(xlo->xlo_backing_file, data, cur_bytes, &pos_read);
+ len = kernel_read(xlo->xlo_backing_file, data + bytes_done, cur_bytes, &pos_read);
flush_dcache_page(bvec->bv_page);
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 15, 0)
kunmap_local(data);