| Message ID | f92d56a113c4b0472df2badb207a699d82deadaf.1725294334.git.javi.merino@cloud.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | libxl: Fixes for libxl_xenconsole_readline() | expand |
On Mon, Sep 02, 2024 at 05:38:38PM +0100, Javi Merino wrote: > When reading the console, xen overwrites the contents of the buffer, > so there is no need to zero the buffer before passing it to xen. > Instead, add a NULL at the end of the buffer. > > While we are at it, change the zalloc() of the buffer back to > malloc() as it was before bdf4131 (libxl: don't leak buf in > libxl_xen_console_read_start error handling, 2013-12-03). The comment > in that commit message says that the intent of the commit was to > change malloc+memset to zalloc(), but only for the > libxl_xen_console_reader struct, not for the buffer. > > Signed-off-by: Javi Merino <javi.merino@cloud.com> Reviewed-by: Anthony PERARD <anthony.perard@vates.tech> Thanks,
diff --git a/tools/libs/light/libxl_console.c b/tools/libs/light/libxl_console.c index 9f736b891335..6c4414fcc1a2 100644 --- a/tools/libs/light/libxl_console.c +++ b/tools/libs/light/libxl_console.c @@ -783,7 +783,7 @@ libxl_xen_console_reader * unsigned int size = 16384 + 1; cr = libxl__zalloc(NOGC, sizeof(libxl_xen_console_reader)); - cr->buffer = libxl__zalloc(NOGC, size); + cr->buffer = libxl__malloc(NOGC, size); cr->size = size; cr->clear = clear; cr->incremental = 1; @@ -813,7 +813,6 @@ int libxl_xen_console_read_line(libxl_ctx *ctx, unsigned int nr_chars = cr->size - 1; GC_INIT(ctx); - memset(cr->buffer, 0, cr->size); ret = xc_readconsolering(ctx->xch, cr->buffer, &nr_chars, cr->clear, cr->incremental, &cr->index); if (ret < 0) { @@ -823,6 +822,7 @@ int libxl_xen_console_read_line(libxl_ctx *ctx, } if (!ret) { if (nr_chars) { + cr->buffer[nr_chars] = '\0'; *line_r = cr->buffer; ret = 1; } else {
When reading the console, xen overwrites the contents of the buffer, so there is no need to zero the buffer before passing it to xen. Instead, add a NULL at the end of the buffer. While we are at it, change the zalloc() of the buffer back to malloc() as it was before bdf4131 (libxl: don't leak buf in libxl_xen_console_read_start error handling, 2013-12-03). The comment in that commit message says that the intent of the commit was to change malloc+memset to zalloc(), but only for the libxl_xen_console_reader struct, not for the buffer. Signed-off-by: Javi Merino <javi.merino@cloud.com> --- tools/libs/light/libxl_console.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)