5b9910f0a
Denys Vlasenko
2013-08-20
Subject
dd: fail if swab is attempted on odd-sized block
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coreutils/dd.c+21 -10
| @@ -151,13 +151,13 @@ int dd_main(int argc UNUSED_PARAM, char **argv) | |
| enum { | |
| /* Must be in the same order as OP_conv_XXX! */ | |
| /* (see "flags |= (1 << what)" below) */ | |
| - | FLAG_NOTRUNC = 1 << 0, |
| - | FLAG_SYNC = 1 << 1, |
| - | FLAG_NOERROR = 1 << 2, |
| - | FLAG_FSYNC = 1 << 3, |
| - | FLAG_SWAB = 1 << 4, |
| + | FLAG_NOTRUNC = (1 << 0) * ENABLE_FEATURE_DD_IBS_OBS, |
| + | FLAG_SYNC = (1 << 1) * ENABLE_FEATURE_DD_IBS_OBS, |
| + | FLAG_NOERROR = (1 << 2) * ENABLE_FEATURE_DD_IBS_OBS, |
| + | FLAG_FSYNC = (1 << 3) * ENABLE_FEATURE_DD_IBS_OBS, |
| + | FLAG_SWAB = (1 << 4) * ENABLE_FEATURE_DD_IBS_OBS, |
| /* end of conv flags */ | |
| - | FLAG_TWOBUFS = 1 << 5, |
| + | FLAG_TWOBUFS = (1 << 5) * ENABLE_FEATURE_DD_IBS_OBS, |
| FLAG_COUNT = 1 << 6, | |
| }; | |
| static const char keywords[] ALIGN1 = | |
| @@ -202,7 +202,7 @@ int dd_main(int argc UNUSED_PARAM, char **argv) | |
| //swab swap every pair of input bytes: will abort on non-even reads | |
| #endif | |
| }; | |
| - | int exitcode = EXIT_FAILURE; |
| + | smallint exitcode = EXIT_FAILURE; |
| size_t ibs = 512, obs = 512; | |
| int i; | |
| char *ibuf, *obuf; | |
| @@ -210,12 +210,14 @@ int dd_main(int argc UNUSED_PARAM, char **argv) | |
| struct { | |
| int flags; | |
| size_t oc; | |
| + | ssize_t prev_read_size; /* for detecting swab failure */ |
| off_t count; | |
| off_t seek, skip; | |
| const char *infile, *outfile; | |
| } Z; | |
| #define flags (Z.flags ) | |
| #define oc (Z.oc ) | |
| + | #define prev_read_size (Z.prev_read_size) |
| #define count (Z.count ) | |
| #define seek (Z.seek ) | |
| #define skip (Z.skip ) | |
| @@ -381,14 +383,23 @@ int dd_main(int argc UNUSED_PARAM, char **argv) | |
| n = 0; | |
| } | |
| if (flags & FLAG_SWAB) { | |
| - | /* If n is odd, last byte is not swapped: |
| + | uint16_t *p16, *end; |
| + | |
| + | /* Our code allows only last read to be odd-sized */ |
| + | if (prev_read_size & 1) |
| + | bb_error_msg_and_die("can't swab %lu byte buffer", |
| + | (unsigned long)prev_read_size); |
| + | prev_read_size = n; |
| + | |
| + | /* |
| + | * If n is odd, last byte is not swapped: |
| * echo -n "qwe" | dd conv=swab | |
| * prints "wqe". | |
| * The code does not handle correctly odd-sized reads | |
| * in the *middle* of the input. FIXME. | |
| */ | |
| - | uint16_t *p16 = (void*) ibuf; |
| - | uint16_t *end = (void*) (ibuf + (n & ~(ssize_t)1)); |
| + | p16 = (void*) ibuf; |
| + | end = (void*) (ibuf + (n & ~(ssize_t)1)); |
| while (p16 < end) { | |
| *p16 = bswap_16(*p16); | |
| p16++; | |