Busybox dd expects that read() calls (as provided by safe_read) will
always return the requested amount of data unless at EOF. This isn't
true for safe_read(), but it is true for full_read() (which loops
over safe_read until enough data has been retrieved).
This patch replaces dd's safe_read() calls with full_read() to make
sure that the underlying assumptions about read-length always hold
true.
Without this patch, users on some platforms can get corrupted reads
or incomplete skips.
Signed-off-by: Nicholas Clark <nicholas.clark at gmail.com>
---
coreutils/dd.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/coreutils/dd.c b/coreutils/dd.c
index d302f35d3..6fc062d8d 100644
--- a/coreutils/dd.c
+++ b/coreutils/dd.c
@@ -450,7 +450,7 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
size_t blocksz = (G.flags & FLAG_SKIP_BYTES) ? 1 : ibs;
if (lseek(ifd, skip * blocksz, SEEK_CUR) < 0) {
do {
- ssize_t n = safe_read(ifd, ibuf, blocksz);
+ ssize_t n = full_read(ifd, ibuf, blocksz);
if (n < 0)
goto die_infile;
if (n == 0)
@@ -466,7 +466,7 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
while (!(G.flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
ssize_t n;
- n = safe_read(ifd, ibuf, ibs);
+ n = full_read(ifd, ibuf, ibs);
if (n == 0)
break;
if (n < 0) {
--
2.11.0
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