fs: btrfs: Fix LZO false decompression error caused by pending zero

[oweals/u-boot.git] / fs / btrfs / compression.c

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 4ef44ce11485d3375b461c33aa0fc68fb82c43e3..b1884fc15ee000110fa03c7b73767a4db8e50697 100644 (file)
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -9,6 +9,7 @@
 #include <malloc.h>
 #include <linux/lzo.h>
 #include <linux/zstd.h>
+#include <linux/compat.h>
 #include <u-boot/zlib.h>
 #include <asm/unaligned.h>
 
@@ -16,7 +17,7 @@
 #define LZO_LEN                4
 static u32 decompress_lzo(const u8 *cbuf, u32 clen, u8 *dbuf, u32 dlen)
 {
-       u32 tot_len, in_len, res;
+       u32 tot_len, tot_in, in_len, res;
        size_t out_len;
        int ret;
 
@@ -24,9 +25,11 @@ static u32 decompress_lzo(const u8 *cbuf, u32 clen, u8 *dbuf, u32 dlen)
                return -1;
 
        tot_len = le32_to_cpu(get_unaligned((u32 *)cbuf));
+       tot_in = 0;
        cbuf += LZO_LEN;
        clen -= LZO_LEN;
        tot_len -= LZO_LEN;
+       tot_in += LZO_LEN;
 
        if (tot_len == 0 && dlen)
                return -1;
@@ -36,6 +39,8 @@ static u32 decompress_lzo(const u8 *cbuf, u32 clen, u8 *dbuf, u32 dlen)
        res = 0;
 
        while (tot_len > LZO_LEN) {
+               u32 rem_page;
+
                in_len = le32_to_cpu(get_unaligned((u32 *)cbuf));
                cbuf += LZO_LEN;
                clen -= LZO_LEN;
@@ -44,6 +49,7 @@ static u32 decompress_lzo(const u8 *cbuf, u32 clen, u8 *dbuf, u32 dlen)
                        return -1;
 
                tot_len -= (LZO_LEN + in_len);
+               tot_in += (LZO_LEN + in_len);
 
                out_len = dlen;
                ret = lzo1x_decompress_safe(cbuf, in_len, dbuf, &out_len);
@@ -56,6 +62,18 @@ static u32 decompress_lzo(const u8 *cbuf, u32 clen, u8 *dbuf, u32 dlen)
                dlen -= out_len;
 
                res += out_len;
+
+               /*
+                * If the 4 bytes header does not fit to the rest of the page we
+                * have to move to next one, or we read some garbage.
+                */
+               rem_page = PAGE_SIZE - (tot_in % PAGE_SIZE);
+               if (rem_page < LZO_LEN) {
+                       cbuf += rem_page;
+                       tot_in += rem_page;
+                       clen -= rem_page;
+                       tot_len -= rem_page;
+               }
        }
 
        return res;